Refactoring logger_test into separate files

This is done because logger_test was getting too big. Now, the
multinode_logger_test is separated out of single node logger_test. This
also allows for anyone to just use the class by sourcing it from
multinode_logger_test_lib

Change-Id: I9814532b646742d9900ad8f5da33a2d9b1d10664
Signed-off-by: Austin Schuh <austin.schuh@bluerivertech.com>
Signed-off-by: Naman Gupta <naman.gupta@bluerivertech.com>
diff --git a/aos/events/logging/multinode_logger_test.cc b/aos/events/logging/multinode_logger_test.cc
new file mode 100644
index 0000000..bc1f5b8
--- /dev/null
+++ b/aos/events/logging/multinode_logger_test.cc
@@ -0,0 +1,3594 @@
+#include "aos/events/logging/log_reader.h"
+#include "aos/events/logging/multinode_logger_test_lib.h"
+#include "aos/events/message_counter.h"
+#include "aos/events/ping_lib.h"
+#include "aos/events/pong_lib.h"
+#include "aos/network/remote_message_generated.h"
+#include "aos/network/timestamp_generated.h"
+#include "aos/testing/tmpdir.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+namespace aos {
+namespace logger {
+namespace testing {
+
+namespace chrono = std::chrono;
+using aos::message_bridge::RemoteMessage;
+using aos::testing::ArtifactPath;
+using aos::testing::MessageCounter;
+
+constexpr std::string_view kCombinedConfigSha1(
+    "5d73fe35bacaa59d24f8f0c1a806fe10b783b0fcc80809ee30a9db824e82538b");
+constexpr std::string_view kSplitConfigSha1(
+    "f25e8f6f90d61f41c41517e652300566228b077e44cd86f1af2af4a9bed31ad4");
+constexpr std::string_view kReloggedSplitConfigSha1(
+    "f1fabd629bdf8735c3d81bc791d7a454e8e636951c26cba6426545cbc97f911f");
+
+INSTANTIATE_TEST_SUITE_P(
+    All, MultinodeLoggerTest,
+    ::testing::Combine(
+        ::testing::Values(
+            ConfigParams{"multinode_pingpong_combined_config.json", true,
+                         kCombinedConfigSha1, kCombinedConfigSha1},
+            ConfigParams{"multinode_pingpong_split_config.json", false,
+                         kSplitConfigSha1, kReloggedSplitConfigSha1}),
+        ::testing::ValuesIn(SupportedCompressionAlgorithms())));
+
+INSTANTIATE_TEST_SUITE_P(
+    All, MultinodeLoggerDeathTest,
+    ::testing::Combine(
+        ::testing::Values(
+            ConfigParams{"multinode_pingpong_combined_config.json", true,
+                         kCombinedConfigSha1, kCombinedConfigSha1},
+            ConfigParams{"multinode_pingpong_split_config.json", false,
+                         kSplitConfigSha1, kReloggedSplitConfigSha1}),
+        ::testing::ValuesIn(SupportedCompressionAlgorithms())));
+
+// Tests that we can write and read simple multi-node log files.
+TEST_P(MultinodeLoggerTest, SimpleMultiNode) {
+  std::vector<std::string> actual_filenames;
+  time_converter_.StartEqual();
+
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(20000));
+    pi1_logger.AppendAllFilenames(&actual_filenames);
+    pi2_logger.AppendAllFilenames(&actual_filenames);
+  }
+
+  ASSERT_THAT(actual_filenames,
+              ::testing::UnorderedElementsAreArray(logfiles_));
+
+  {
+    std::set<std::string> logfile_uuids;
+    std::set<std::string> parts_uuids;
+    // Confirm that we have the expected number of UUIDs for both the logfile
+    // UUIDs and parts UUIDs.
+    std::vector<SizePrefixedFlatbufferVector<LogFileHeader>> log_header;
+    for (std::string_view f : logfiles_) {
+      log_header.emplace_back(ReadHeader(f).value());
+      if (!log_header.back().message().has_configuration()) {
+        logfile_uuids.insert(
+            log_header.back().message().log_event_uuid()->str());
+        parts_uuids.insert(log_header.back().message().parts_uuid()->str());
+      }
+    }
+
+    EXPECT_EQ(logfile_uuids.size(), 2u);
+    if (shared()) {
+      EXPECT_EQ(parts_uuids.size(), 7u);
+    } else {
+      EXPECT_EQ(parts_uuids.size(), 8u);
+    }
+
+    // And confirm everything is on the correct node.
+    EXPECT_EQ(log_header[2].message().node()->name()->string_view(), "pi1");
+    EXPECT_EQ(log_header[3].message().node()->name()->string_view(), "pi1");
+    EXPECT_EQ(log_header[4].message().node()->name()->string_view(), "pi1");
+
+    EXPECT_EQ(log_header[5].message().node()->name()->string_view(), "pi2");
+    EXPECT_EQ(log_header[6].message().node()->name()->string_view(), "pi2");
+
+    EXPECT_EQ(log_header[7].message().node()->name()->string_view(), "pi2");
+    EXPECT_EQ(log_header[8].message().node()->name()->string_view(), "pi2");
+    EXPECT_EQ(log_header[9].message().node()->name()->string_view(), "pi2");
+
+    EXPECT_EQ(log_header[10].message().node()->name()->string_view(), "pi1");
+    EXPECT_EQ(log_header[11].message().node()->name()->string_view(), "pi1");
+
+    EXPECT_EQ(log_header[12].message().node()->name()->string_view(), "pi2");
+    EXPECT_EQ(log_header[13].message().node()->name()->string_view(), "pi2");
+
+    if (shared()) {
+      EXPECT_EQ(log_header[14].message().node()->name()->string_view(), "pi2");
+      EXPECT_EQ(log_header[15].message().node()->name()->string_view(), "pi2");
+      EXPECT_EQ(log_header[16].message().node()->name()->string_view(), "pi2");
+
+      EXPECT_EQ(log_header[17].message().node()->name()->string_view(), "pi1");
+      EXPECT_EQ(log_header[18].message().node()->name()->string_view(), "pi1");
+    } else {
+      EXPECT_EQ(log_header[14].message().node()->name()->string_view(), "pi2");
+      EXPECT_EQ(log_header[15].message().node()->name()->string_view(), "pi2");
+
+      EXPECT_EQ(log_header[16].message().node()->name()->string_view(), "pi1");
+      EXPECT_EQ(log_header[17].message().node()->name()->string_view(), "pi1");
+
+      EXPECT_EQ(log_header[18].message().node()->name()->string_view(), "pi2");
+      EXPECT_EQ(log_header[19].message().node()->name()->string_view(), "pi2");
+    }
+
+    // And the parts index matches.
+    EXPECT_EQ(log_header[2].message().parts_index(), 0);
+    EXPECT_EQ(log_header[3].message().parts_index(), 1);
+    EXPECT_EQ(log_header[4].message().parts_index(), 2);
+
+    EXPECT_EQ(log_header[5].message().parts_index(), 0);
+    EXPECT_EQ(log_header[6].message().parts_index(), 1);
+
+    EXPECT_EQ(log_header[7].message().parts_index(), 0);
+    EXPECT_EQ(log_header[8].message().parts_index(), 1);
+    EXPECT_EQ(log_header[9].message().parts_index(), 2);
+
+    EXPECT_EQ(log_header[10].message().parts_index(), 0);
+    EXPECT_EQ(log_header[11].message().parts_index(), 1);
+
+    EXPECT_EQ(log_header[12].message().parts_index(), 0);
+    EXPECT_EQ(log_header[13].message().parts_index(), 1);
+
+    if (shared()) {
+      EXPECT_EQ(log_header[14].message().parts_index(), 0);
+      EXPECT_EQ(log_header[15].message().parts_index(), 1);
+      EXPECT_EQ(log_header[16].message().parts_index(), 2);
+
+      EXPECT_EQ(log_header[17].message().parts_index(), 0);
+      EXPECT_EQ(log_header[18].message().parts_index(), 1);
+    } else {
+      EXPECT_EQ(log_header[14].message().parts_index(), 0);
+      EXPECT_EQ(log_header[15].message().parts_index(), 1);
+
+      EXPECT_EQ(log_header[16].message().parts_index(), 0);
+      EXPECT_EQ(log_header[17].message().parts_index(), 1);
+
+      EXPECT_EQ(log_header[18].message().parts_index(), 0);
+      EXPECT_EQ(log_header[19].message().parts_index(), 1);
+    }
+  }
+
+  const std::vector<LogFile> sorted_log_files = SortParts(logfiles_);
+  {
+    using ::testing::UnorderedElementsAre;
+    std::shared_ptr<const aos::Configuration> config =
+        sorted_log_files[0].config;
+
+    // Timing reports, pings
+    EXPECT_THAT(CountChannelsData(config, logfiles_[2]),
+                UnorderedElementsAre(
+                    std::make_tuple("/pi1/aos",
+                                    "aos.message_bridge.ServerStatistics", 1),
+                    std::make_tuple("/test", "aos.examples.Ping", 1)))
+        << " : " << logfiles_[2];
+    {
+      std::vector<std::tuple<std::string, std::string, int>> channel_counts = {
+          std::make_tuple("/pi1/aos", "aos.message_bridge.Timestamp", 1),
+          std::make_tuple("/pi1/aos", "aos.message_bridge.ClientStatistics",
+                          1)};
+      if (!std::get<0>(GetParam()).shared) {
+        channel_counts.push_back(
+            std::make_tuple("/pi1/aos/remote_timestamps/pi2/pi1/aos/"
+                            "aos-message_bridge-Timestamp",
+                            "aos.message_bridge.RemoteMessage", 1));
+      }
+      EXPECT_THAT(CountChannelsData(config, logfiles_[3]),
+                  ::testing::UnorderedElementsAreArray(channel_counts))
+          << " : " << logfiles_[3];
+    }
+    {
+      std::vector<std::tuple<std::string, std::string, int>> channel_counts = {
+          std::make_tuple("/pi1/aos", "aos.message_bridge.Timestamp", 199),
+          std::make_tuple("/pi1/aos", "aos.message_bridge.ServerStatistics",
+                          20),
+          std::make_tuple("/pi1/aos", "aos.message_bridge.ClientStatistics",
+                          199),
+          std::make_tuple("/pi1/aos", "aos.timing.Report", 40),
+          std::make_tuple("/test", "aos.examples.Ping", 2000)};
+      if (!std::get<0>(GetParam()).shared) {
+        channel_counts.push_back(
+            std::make_tuple("/pi1/aos/remote_timestamps/pi2/pi1/aos/"
+                            "aos-message_bridge-Timestamp",
+                            "aos.message_bridge.RemoteMessage", 199));
+      }
+      EXPECT_THAT(CountChannelsData(config, logfiles_[4]),
+                  ::testing::UnorderedElementsAreArray(channel_counts))
+          << " : " << logfiles_[4];
+    }
+    // Timestamps for pong
+    EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[2]),
+                UnorderedElementsAre())
+        << " : " << logfiles_[2];
+    EXPECT_THAT(
+        CountChannelsTimestamp(config, logfiles_[3]),
+        UnorderedElementsAre(std::make_tuple("/test", "aos.examples.Pong", 1)))
+        << " : " << logfiles_[3];
+    EXPECT_THAT(
+        CountChannelsTimestamp(config, logfiles_[4]),
+        UnorderedElementsAre(
+            std::make_tuple("/test", "aos.examples.Pong", 2000),
+            std::make_tuple("/pi2/aos", "aos.message_bridge.Timestamp", 200)))
+        << " : " << logfiles_[4];
+
+    // Pong data.
+    EXPECT_THAT(
+        CountChannelsData(config, logfiles_[5]),
+        UnorderedElementsAre(std::make_tuple("/test", "aos.examples.Pong", 91)))
+        << " : " << logfiles_[5];
+    EXPECT_THAT(CountChannelsData(config, logfiles_[6]),
+                UnorderedElementsAre(
+                    std::make_tuple("/test", "aos.examples.Pong", 1910)))
+        << " : " << logfiles_[6];
+
+    // No timestamps
+    EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[5]),
+                UnorderedElementsAre())
+        << " : " << logfiles_[5];
+    EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[6]),
+                UnorderedElementsAre())
+        << " : " << logfiles_[6];
+
+    // Timing reports and pongs.
+    EXPECT_THAT(CountChannelsData(config, logfiles_[7]),
+                UnorderedElementsAre(std::make_tuple(
+                    "/pi2/aos", "aos.message_bridge.ServerStatistics", 1)))
+        << " : " << logfiles_[7];
+    EXPECT_THAT(
+        CountChannelsData(config, logfiles_[8]),
+        UnorderedElementsAre(std::make_tuple("/test", "aos.examples.Pong", 1)))
+        << " : " << logfiles_[8];
+    EXPECT_THAT(
+        CountChannelsData(config, logfiles_[9]),
+        UnorderedElementsAre(
+            std::make_tuple("/pi2/aos", "aos.message_bridge.Timestamp", 200),
+            std::make_tuple("/pi2/aos", "aos.message_bridge.ServerStatistics",
+                            20),
+            std::make_tuple("/pi2/aos", "aos.message_bridge.ClientStatistics",
+                            200),
+            std::make_tuple("/pi2/aos", "aos.timing.Report", 40),
+            std::make_tuple("/test", "aos.examples.Pong", 2000)))
+        << " : " << logfiles_[9];
+    // And ping timestamps.
+    EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[7]),
+                UnorderedElementsAre())
+        << " : " << logfiles_[7];
+    EXPECT_THAT(
+        CountChannelsTimestamp(config, logfiles_[8]),
+        UnorderedElementsAre(std::make_tuple("/test", "aos.examples.Ping", 1)))
+        << " : " << logfiles_[8];
+    EXPECT_THAT(
+        CountChannelsTimestamp(config, logfiles_[9]),
+        UnorderedElementsAre(
+            std::make_tuple("/test", "aos.examples.Ping", 2000),
+            std::make_tuple("/pi1/aos", "aos.message_bridge.Timestamp", 200)))
+        << " : " << logfiles_[9];
+
+    // And then test that the remotely logged timestamp data files only have
+    // timestamps in them.
+    EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[10]),
+                UnorderedElementsAre())
+        << " : " << logfiles_[10];
+    EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[11]),
+                UnorderedElementsAre())
+        << " : " << logfiles_[11];
+    EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[12]),
+                UnorderedElementsAre())
+        << " : " << logfiles_[12];
+    EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[13]),
+                UnorderedElementsAre())
+        << " : " << logfiles_[13];
+
+    EXPECT_THAT(CountChannelsData(config, logfiles_[10]),
+                UnorderedElementsAre(std::make_tuple(
+                    "/pi1/aos", "aos.message_bridge.Timestamp", 9)))
+        << " : " << logfiles_[10];
+    EXPECT_THAT(CountChannelsData(config, logfiles_[11]),
+                UnorderedElementsAre(std::make_tuple(
+                    "/pi1/aos", "aos.message_bridge.Timestamp", 191)))
+        << " : " << logfiles_[11];
+
+    EXPECT_THAT(CountChannelsData(config, logfiles_[12]),
+                UnorderedElementsAre(std::make_tuple(
+                    "/pi2/aos", "aos.message_bridge.Timestamp", 9)))
+        << " : " << logfiles_[12];
+    EXPECT_THAT(CountChannelsData(config, logfiles_[13]),
+                UnorderedElementsAre(std::make_tuple(
+                    "/pi2/aos", "aos.message_bridge.Timestamp", 191)))
+        << " : " << logfiles_[13];
+
+    // Timestamps from pi2 on pi1, and the other way.
+    if (shared()) {
+      EXPECT_THAT(CountChannelsData(config, logfiles_[14]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[14];
+      EXPECT_THAT(CountChannelsData(config, logfiles_[15]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[15];
+      EXPECT_THAT(CountChannelsData(config, logfiles_[16]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[16];
+      EXPECT_THAT(CountChannelsData(config, logfiles_[17]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[17];
+      EXPECT_THAT(CountChannelsData(config, logfiles_[18]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[18];
+
+      EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[14]),
+                  UnorderedElementsAre(
+                      std::make_tuple("/test", "aos.examples.Ping", 1)))
+          << " : " << logfiles_[14];
+      EXPECT_THAT(
+          CountChannelsTimestamp(config, logfiles_[15]),
+          UnorderedElementsAre(
+              std::make_tuple("/pi1/aos", "aos.message_bridge.Timestamp", 9),
+              std::make_tuple("/test", "aos.examples.Ping", 90)))
+          << " : " << logfiles_[15];
+      EXPECT_THAT(
+          CountChannelsTimestamp(config, logfiles_[16]),
+          UnorderedElementsAre(
+              std::make_tuple("/pi1/aos", "aos.message_bridge.Timestamp", 191),
+              std::make_tuple("/test", "aos.examples.Ping", 1910)))
+          << " : " << logfiles_[16];
+      EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[17]),
+                  UnorderedElementsAre(std::make_tuple(
+                      "/pi2/aos", "aos.message_bridge.Timestamp", 9)))
+          << " : " << logfiles_[17];
+      EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[18]),
+                  UnorderedElementsAre(std::make_tuple(
+                      "/pi2/aos", "aos.message_bridge.Timestamp", 191)))
+          << " : " << logfiles_[18];
+    } else {
+      EXPECT_THAT(CountChannelsData(config, logfiles_[14]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[14];
+      EXPECT_THAT(CountChannelsData(config, logfiles_[15]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[15];
+      EXPECT_THAT(CountChannelsData(config, logfiles_[16]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[16];
+      EXPECT_THAT(CountChannelsData(config, logfiles_[17]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[17];
+      EXPECT_THAT(CountChannelsData(config, logfiles_[18]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[18];
+      EXPECT_THAT(CountChannelsData(config, logfiles_[19]),
+                  UnorderedElementsAre())
+          << " : " << logfiles_[19];
+
+      EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[14]),
+                  UnorderedElementsAre(std::make_tuple(
+                      "/pi1/aos", "aos.message_bridge.Timestamp", 9)))
+          << " : " << logfiles_[14];
+      EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[15]),
+                  UnorderedElementsAre(std::make_tuple(
+                      "/pi1/aos", "aos.message_bridge.Timestamp", 191)))
+          << " : " << logfiles_[15];
+      EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[16]),
+                  UnorderedElementsAre(std::make_tuple(
+                      "/pi2/aos", "aos.message_bridge.Timestamp", 9)))
+          << " : " << logfiles_[16];
+      EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[17]),
+                  UnorderedElementsAre(std::make_tuple(
+                      "/pi2/aos", "aos.message_bridge.Timestamp", 191)))
+          << " : " << logfiles_[17];
+      EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[18]),
+                  UnorderedElementsAre(
+                      std::make_tuple("/test", "aos.examples.Ping", 91)))
+          << " : " << logfiles_[18];
+      EXPECT_THAT(CountChannelsTimestamp(config, logfiles_[19]),
+                  UnorderedElementsAre(
+                      std::make_tuple("/test", "aos.examples.Ping", 1910)))
+          << " : " << logfiles_[19];
+    }
+  }
+
+  LogReader reader(sorted_log_files);
+
+  SimulatedEventLoopFactory log_reader_factory(reader.configuration());
+  log_reader_factory.set_send_delay(chrono::microseconds(0));
+
+  // This sends out the fetched messages and advances time to the start of the
+  // log file.
+  reader.Register(&log_reader_factory);
+
+  const Node *pi1 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi1");
+  const Node *pi2 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi2");
+
+  LOG(INFO) << "Start time " << reader.monotonic_start_time(pi1) << " pi1";
+  LOG(INFO) << "Start time " << reader.monotonic_start_time(pi2) << " pi2";
+  LOG(INFO) << "now pi1 "
+            << log_reader_factory.GetNodeEventLoopFactory(pi1)->monotonic_now();
+  LOG(INFO) << "now pi2 "
+            << log_reader_factory.GetNodeEventLoopFactory(pi2)->monotonic_now();
+
+  EXPECT_THAT(reader.LoggedNodes(),
+              ::testing::ElementsAre(
+                  configuration::GetNode(reader.logged_configuration(), pi1),
+                  configuration::GetNode(reader.logged_configuration(), pi2)));
+
+  reader.event_loop_factory()->set_send_delay(chrono::microseconds(0));
+
+  std::unique_ptr<EventLoop> pi1_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi1);
+  std::unique_ptr<EventLoop> pi2_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi2);
+
+  int pi1_ping_count = 10;
+  int pi2_ping_count = 10;
+  int pi1_pong_count = 10;
+  int pi2_pong_count = 10;
+
+  // Confirm that the ping value matches.
+  pi1_event_loop->MakeWatcher(
+      "/test", [&pi1_ping_count, &pi1_event_loop](const examples::Ping &ping) {
+        VLOG(1) << "Pi1 ping " << FlatbufferToJson(&ping) << " at "
+                << pi1_event_loop->context().monotonic_remote_time << " -> "
+                << pi1_event_loop->context().monotonic_event_time;
+        EXPECT_EQ(ping.value(), pi1_ping_count + 1);
+        EXPECT_EQ(pi1_event_loop->context().monotonic_remote_time,
+                  pi1_ping_count * chrono::milliseconds(10) +
+                      monotonic_clock::epoch());
+        EXPECT_EQ(pi1_event_loop->context().realtime_remote_time,
+                  pi1_ping_count * chrono::milliseconds(10) +
+                      realtime_clock::epoch());
+        EXPECT_EQ(pi1_event_loop->context().monotonic_remote_time,
+                  pi1_event_loop->context().monotonic_event_time);
+        EXPECT_EQ(pi1_event_loop->context().realtime_remote_time,
+                  pi1_event_loop->context().realtime_event_time);
+
+        ++pi1_ping_count;
+      });
+  pi2_event_loop->MakeWatcher(
+      "/test", [&pi2_ping_count, &pi2_event_loop](const examples::Ping &ping) {
+        VLOG(1) << "Pi2 ping " << FlatbufferToJson(&ping) << " at "
+                << pi2_event_loop->context().monotonic_remote_time << " -> "
+                << pi2_event_loop->context().monotonic_event_time;
+        EXPECT_EQ(ping.value(), pi2_ping_count + 1);
+
+        EXPECT_EQ(pi2_event_loop->context().monotonic_remote_time,
+                  pi2_ping_count * chrono::milliseconds(10) +
+                      monotonic_clock::epoch());
+        EXPECT_EQ(pi2_event_loop->context().realtime_remote_time,
+                  pi2_ping_count * chrono::milliseconds(10) +
+                      realtime_clock::epoch());
+        EXPECT_EQ(pi2_event_loop->context().monotonic_remote_time +
+                      chrono::microseconds(150),
+                  pi2_event_loop->context().monotonic_event_time);
+        EXPECT_EQ(pi2_event_loop->context().realtime_remote_time +
+                      chrono::microseconds(150),
+                  pi2_event_loop->context().realtime_event_time);
+        ++pi2_ping_count;
+      });
+
+  constexpr ssize_t kQueueIndexOffset = -9;
+  // Confirm that the ping and pong counts both match, and the value also
+  // matches.
+  pi1_event_loop->MakeWatcher(
+      "/test", [&pi1_event_loop, &pi1_ping_count,
+                &pi1_pong_count](const examples::Pong &pong) {
+        VLOG(1) << "Pi1 pong " << FlatbufferToJson(&pong) << " at "
+                << pi1_event_loop->context().monotonic_remote_time << " -> "
+                << pi1_event_loop->context().monotonic_event_time;
+
+        EXPECT_EQ(pi1_event_loop->context().remote_queue_index,
+                  pi1_pong_count + kQueueIndexOffset);
+        EXPECT_EQ(pi1_event_loop->context().monotonic_remote_time,
+                  chrono::microseconds(200) +
+                      pi1_pong_count * chrono::milliseconds(10) +
+                      monotonic_clock::epoch());
+        EXPECT_EQ(pi1_event_loop->context().realtime_remote_time,
+                  chrono::microseconds(200) +
+                      pi1_pong_count * chrono::milliseconds(10) +
+                      realtime_clock::epoch());
+
+        EXPECT_EQ(pi1_event_loop->context().monotonic_remote_time +
+                      chrono::microseconds(150),
+                  pi1_event_loop->context().monotonic_event_time);
+        EXPECT_EQ(pi1_event_loop->context().realtime_remote_time +
+                      chrono::microseconds(150),
+                  pi1_event_loop->context().realtime_event_time);
+
+        EXPECT_EQ(pong.value(), pi1_pong_count + 1);
+        ++pi1_pong_count;
+        EXPECT_EQ(pi1_ping_count, pi1_pong_count);
+      });
+  pi2_event_loop->MakeWatcher(
+      "/test", [&pi2_event_loop, &pi2_ping_count,
+                &pi2_pong_count](const examples::Pong &pong) {
+        VLOG(1) << "Pi2 pong " << FlatbufferToJson(&pong) << " at "
+                << pi2_event_loop->context().monotonic_remote_time << " -> "
+                << pi2_event_loop->context().monotonic_event_time;
+
+        EXPECT_EQ(pi2_event_loop->context().remote_queue_index,
+                  pi2_pong_count + kQueueIndexOffset);
+
+        EXPECT_EQ(pi2_event_loop->context().monotonic_remote_time,
+                  chrono::microseconds(200) +
+                      pi2_pong_count * chrono::milliseconds(10) +
+                      monotonic_clock::epoch());
+        EXPECT_EQ(pi2_event_loop->context().realtime_remote_time,
+                  chrono::microseconds(200) +
+                      pi2_pong_count * chrono::milliseconds(10) +
+                      realtime_clock::epoch());
+
+        EXPECT_EQ(pi2_event_loop->context().monotonic_remote_time,
+                  pi2_event_loop->context().monotonic_event_time);
+        EXPECT_EQ(pi2_event_loop->context().realtime_remote_time,
+                  pi2_event_loop->context().realtime_event_time);
+
+        EXPECT_EQ(pong.value(), pi2_pong_count + 1);
+        ++pi2_pong_count;
+        EXPECT_EQ(pi2_ping_count, pi2_pong_count);
+      });
+
+  log_reader_factory.Run();
+  EXPECT_EQ(pi1_ping_count, 2010);
+  EXPECT_EQ(pi2_ping_count, 2010);
+  EXPECT_EQ(pi1_pong_count, 2010);
+  EXPECT_EQ(pi2_pong_count, 2010);
+
+  reader.Deregister();
+}
+
+// Test that if we feed the replay with a mismatched node list that we die on
+// the LogReader constructor.
+TEST_P(MultinodeLoggerDeathTest, MultiNodeBadReplayConfig) {
+  time_converter_.StartEqual();
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(20000));
+  }
+
+  // Test that, if we add an additional node to the replay config that the
+  // logger complains about the mismatch in number of nodes.
+  FlatbufferDetachedBuffer<Configuration> extra_nodes_config =
+      configuration::MergeWithConfig(&config_.message(), R"({
+          "nodes": [
+            {
+              "name": "extra-node"
+            }
+          ]
+        }
+      )");
+
+  const std::vector<LogFile> sorted_parts = SortParts(logfiles_);
+  EXPECT_DEATH(LogReader(sorted_parts, &extra_nodes_config.message()),
+               "Log file and replay config need to have matching nodes lists.");
+}
+
+// Tests that we can read log files where they don't start at the same monotonic
+// time.
+TEST_P(MultinodeLoggerTest, StaggeredStart) {
+  time_converter_.StartEqual();
+  std::vector<std::string> actual_filenames;
+
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(200));
+
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(20000));
+    pi1_logger.AppendAllFilenames(&actual_filenames);
+    pi2_logger.AppendAllFilenames(&actual_filenames);
+  }
+
+  // Since we delay starting pi2, it already knows about all the timestamps so
+  // we don't end up with extra parts.
+  LogReader reader(SortParts(actual_filenames));
+
+  SimulatedEventLoopFactory log_reader_factory(reader.configuration());
+  log_reader_factory.set_send_delay(chrono::microseconds(0));
+
+  // This sends out the fetched messages and advances time to the start of the
+  // log file.
+  reader.Register(&log_reader_factory);
+
+  const Node *pi1 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi1");
+  const Node *pi2 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi2");
+
+  EXPECT_THAT(reader.LoggedNodes(),
+              ::testing::ElementsAre(
+                  configuration::GetNode(reader.logged_configuration(), pi1),
+                  configuration::GetNode(reader.logged_configuration(), pi2)));
+
+  reader.event_loop_factory()->set_send_delay(chrono::microseconds(0));
+
+  std::unique_ptr<EventLoop> pi1_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi1);
+  std::unique_ptr<EventLoop> pi2_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi2);
+
+  int pi1_ping_count = 30;
+  int pi2_ping_count = 30;
+  int pi1_pong_count = 30;
+  int pi2_pong_count = 30;
+
+  // Confirm that the ping value matches.
+  pi1_event_loop->MakeWatcher(
+      "/test", [&pi1_ping_count, &pi1_event_loop](const examples::Ping &ping) {
+        VLOG(1) << "Pi1 ping " << FlatbufferToJson(&ping)
+                << pi1_event_loop->context().monotonic_remote_time << " -> "
+                << pi1_event_loop->context().monotonic_event_time;
+        EXPECT_EQ(ping.value(), pi1_ping_count + 1);
+
+        ++pi1_ping_count;
+      });
+  pi2_event_loop->MakeWatcher(
+      "/test", [&pi2_ping_count, &pi2_event_loop](const examples::Ping &ping) {
+        VLOG(1) << "Pi2 ping " << FlatbufferToJson(&ping)
+                << pi2_event_loop->context().monotonic_remote_time << " -> "
+                << pi2_event_loop->context().monotonic_event_time;
+        EXPECT_EQ(ping.value(), pi2_ping_count + 1);
+
+        ++pi2_ping_count;
+      });
+
+  // Confirm that the ping and pong counts both match, and the value also
+  // matches.
+  pi1_event_loop->MakeWatcher(
+      "/test", [&pi1_event_loop, &pi1_ping_count,
+                &pi1_pong_count](const examples::Pong &pong) {
+        VLOG(1) << "Pi1 pong " << FlatbufferToJson(&pong) << " at "
+                << pi1_event_loop->context().monotonic_remote_time << " -> "
+                << pi1_event_loop->context().monotonic_event_time;
+
+        EXPECT_EQ(pong.value(), pi1_pong_count + 1);
+        ++pi1_pong_count;
+        EXPECT_EQ(pi1_ping_count, pi1_pong_count);
+      });
+  pi2_event_loop->MakeWatcher(
+      "/test", [&pi2_event_loop, &pi2_ping_count,
+                &pi2_pong_count](const examples::Pong &pong) {
+        VLOG(1) << "Pi2 pong " << FlatbufferToJson(&pong) << " at "
+                << pi2_event_loop->context().monotonic_remote_time << " -> "
+                << pi2_event_loop->context().monotonic_event_time;
+
+        EXPECT_EQ(pong.value(), pi2_pong_count + 1);
+        ++pi2_pong_count;
+        EXPECT_EQ(pi2_ping_count, pi2_pong_count);
+      });
+
+  log_reader_factory.Run();
+  EXPECT_EQ(pi1_ping_count, 2030);
+  EXPECT_EQ(pi2_ping_count, 2030);
+  EXPECT_EQ(pi1_pong_count, 2030);
+  EXPECT_EQ(pi2_pong_count, 2030);
+
+  reader.Deregister();
+}
+
+// Tests that we can read log files where the monotonic clocks drift and don't
+// match correctly.  While we are here, also test that different ending times
+// also is readable.
+TEST_P(MultinodeLoggerTest, MismatchedClocks) {
+  // TODO(austin): Negate...
+  const chrono::nanoseconds initial_pi2_offset = chrono::seconds(1000);
+
+  time_converter_.AddMonotonic(
+      {BootTimestamp::epoch(), BootTimestamp::epoch() + initial_pi2_offset});
+  // Wait for 95 ms, (~0.1 seconds - 1/2 of the ping/pong period), and set the
+  // skew to be 200 uS/s
+  const chrono::nanoseconds startup_sleep1 = time_converter_.AddMonotonic(
+      {chrono::milliseconds(95),
+       chrono::milliseconds(95) - chrono::nanoseconds(200) * 95});
+  // Run another 200 ms to have one logger start first.
+  const chrono::nanoseconds startup_sleep2 = time_converter_.AddMonotonic(
+      {chrono::milliseconds(200), chrono::milliseconds(200)});
+  // Slew one way then the other at the same 200 uS/S slew rate.  Make sure we
+  // go far enough to cause problems if this isn't accounted for.
+  const chrono::nanoseconds logger_run1 = time_converter_.AddMonotonic(
+      {chrono::milliseconds(20000),
+       chrono::milliseconds(20000) - chrono::nanoseconds(200) * 20000});
+  const chrono::nanoseconds logger_run2 = time_converter_.AddMonotonic(
+      {chrono::milliseconds(40000),
+       chrono::milliseconds(40000) + chrono::nanoseconds(200) * 40000});
+  const chrono::nanoseconds logger_run3 = time_converter_.AddMonotonic(
+      {chrono::milliseconds(400), chrono::milliseconds(400)});
+
+  {
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    LOG(INFO) << "pi2 times: " << pi2_->monotonic_now() << " "
+              << pi2_->realtime_now() << " distributed "
+              << pi2_->ToDistributedClock(pi2_->monotonic_now());
+
+    LOG(INFO) << "pi2_ times: " << pi2_->monotonic_now() << " "
+              << pi2_->realtime_now() << " distributed "
+              << pi2_->ToDistributedClock(pi2_->monotonic_now());
+
+    event_loop_factory_.RunFor(startup_sleep1);
+
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(startup_sleep2);
+
+    {
+      // Run pi1's logger for only part of the time.
+      LoggerState pi1_logger = MakeLogger(pi1_);
+
+      StartLogger(&pi1_logger);
+      event_loop_factory_.RunFor(logger_run1);
+
+      // Make sure we slewed time far enough so that the difference is greater
+      // than the network delay.  This confirms that if we sort incorrectly, it
+      // would show in the results.
+      EXPECT_LT(
+          (pi2_->monotonic_now() - pi1_->monotonic_now()) - initial_pi2_offset,
+          -event_loop_factory_.send_delay() -
+              event_loop_factory_.network_delay());
+
+      event_loop_factory_.RunFor(logger_run2);
+
+      // And now check that we went far enough the other way to make sure we
+      // cover both problems.
+      EXPECT_GT(
+          (pi2_->monotonic_now() - pi1_->monotonic_now()) - initial_pi2_offset,
+          event_loop_factory_.send_delay() +
+              event_loop_factory_.network_delay());
+    }
+
+    // And log a bit more on pi2.
+    event_loop_factory_.RunFor(logger_run3);
+  }
+
+  LogReader reader(
+      SortParts(MakeLogFiles(logfile_base1_, logfile_base2_, 3, 2)));
+
+  SimulatedEventLoopFactory log_reader_factory(reader.configuration());
+  log_reader_factory.set_send_delay(chrono::microseconds(0));
+
+  const Node *pi1 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi1");
+  const Node *pi2 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi2");
+
+  // This sends out the fetched messages and advances time to the start of the
+  // log file.
+  reader.Register(&log_reader_factory);
+
+  LOG(INFO) << "Start time " << reader.monotonic_start_time(pi1) << " pi1";
+  LOG(INFO) << "Start time " << reader.monotonic_start_time(pi2) << " pi2";
+  LOG(INFO) << "now pi1 "
+            << log_reader_factory.GetNodeEventLoopFactory(pi1)->monotonic_now();
+  LOG(INFO) << "now pi2 "
+            << log_reader_factory.GetNodeEventLoopFactory(pi2)->monotonic_now();
+
+  LOG(INFO) << "Done registering (pi1) "
+            << log_reader_factory.GetNodeEventLoopFactory(pi1)->monotonic_now()
+            << " "
+            << log_reader_factory.GetNodeEventLoopFactory(pi1)->realtime_now();
+  LOG(INFO) << "Done registering (pi2) "
+            << log_reader_factory.GetNodeEventLoopFactory(pi2)->monotonic_now()
+            << " "
+            << log_reader_factory.GetNodeEventLoopFactory(pi2)->realtime_now();
+
+  EXPECT_THAT(reader.LoggedNodes(),
+              ::testing::ElementsAre(
+                  configuration::GetNode(reader.logged_configuration(), pi1),
+                  configuration::GetNode(reader.logged_configuration(), pi2)));
+
+  reader.event_loop_factory()->set_send_delay(chrono::microseconds(0));
+
+  std::unique_ptr<EventLoop> pi1_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi1);
+  std::unique_ptr<EventLoop> pi2_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi2);
+
+  int pi1_ping_count = 30;
+  int pi2_ping_count = 30;
+  int pi1_pong_count = 30;
+  int pi2_pong_count = 30;
+
+  // Confirm that the ping value matches.
+  pi1_event_loop->MakeWatcher(
+      "/test", [&pi1_ping_count, &pi1_event_loop](const examples::Ping &ping) {
+        VLOG(1) << "Pi1 ping " << FlatbufferToJson(&ping)
+                << pi1_event_loop->context().monotonic_remote_time << " -> "
+                << pi1_event_loop->context().monotonic_event_time;
+        EXPECT_EQ(ping.value(), pi1_ping_count + 1);
+
+        ++pi1_ping_count;
+      });
+  pi2_event_loop->MakeWatcher(
+      "/test", [&pi2_ping_count, &pi2_event_loop](const examples::Ping &ping) {
+        VLOG(1) << "Pi2 ping " << FlatbufferToJson(&ping)
+                << pi2_event_loop->context().monotonic_remote_time << " -> "
+                << pi2_event_loop->context().monotonic_event_time;
+        EXPECT_EQ(ping.value(), pi2_ping_count + 1);
+
+        ++pi2_ping_count;
+      });
+
+  // Confirm that the ping and pong counts both match, and the value also
+  // matches.
+  pi1_event_loop->MakeWatcher(
+      "/test", [&pi1_event_loop, &pi1_ping_count,
+                &pi1_pong_count](const examples::Pong &pong) {
+        VLOG(1) << "Pi1 pong " << FlatbufferToJson(&pong) << " at "
+                << pi1_event_loop->context().monotonic_remote_time << " -> "
+                << pi1_event_loop->context().monotonic_event_time;
+
+        EXPECT_EQ(pong.value(), pi1_pong_count + 1);
+        ++pi1_pong_count;
+        EXPECT_EQ(pi1_ping_count, pi1_pong_count);
+      });
+  pi2_event_loop->MakeWatcher(
+      "/test", [&pi2_event_loop, &pi2_ping_count,
+                &pi2_pong_count](const examples::Pong &pong) {
+        VLOG(1) << "Pi2 pong " << FlatbufferToJson(&pong) << " at "
+                << pi2_event_loop->context().monotonic_remote_time << " -> "
+                << pi2_event_loop->context().monotonic_event_time;
+
+        EXPECT_EQ(pong.value(), pi2_pong_count + 1);
+        ++pi2_pong_count;
+        EXPECT_EQ(pi2_ping_count, pi2_pong_count);
+      });
+
+  log_reader_factory.Run();
+  EXPECT_EQ(pi1_ping_count, 6030);
+  EXPECT_EQ(pi2_ping_count, 6030);
+  EXPECT_EQ(pi1_pong_count, 6030);
+  EXPECT_EQ(pi2_pong_count, 6030);
+
+  reader.Deregister();
+}
+
+// Tests that we can sort a bunch of parts into the pre-determined sorted parts.
+TEST_P(MultinodeLoggerTest, SortParts) {
+  time_converter_.StartEqual();
+  // Make a bunch of parts.
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(2000));
+  }
+
+  const std::vector<LogFile> sorted_parts = SortParts(logfiles_);
+  VerifyParts(sorted_parts);
+}
+
+// Tests that we can sort a bunch of parts with an empty part.  We should ignore
+// it and remove it from the sorted list.
+TEST_P(MultinodeLoggerTest, SortEmptyParts) {
+  time_converter_.StartEqual();
+  // Make a bunch of parts.
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(2000));
+  }
+
+  // TODO(austin): Should we flip out if the file can't open?
+  const std::string kEmptyFile("foobarinvalidfiledoesnotexist" + Extension());
+
+  aos::util::WriteStringToFileOrDie(kEmptyFile, "");
+  logfiles_.emplace_back(kEmptyFile);
+
+  const std::vector<LogFile> sorted_parts = SortParts(logfiles_);
+  VerifyParts(sorted_parts, {kEmptyFile});
+}
+
+// Tests that we can sort a bunch of parts with the end missing off a
+// file.  We should use the part we can read.
+TEST_P(MultinodeLoggerTest, SortTruncatedParts) {
+  std::vector<std::string> actual_filenames;
+  time_converter_.StartEqual();
+  // Make a bunch of parts.
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(2000));
+
+    pi1_logger.AppendAllFilenames(&actual_filenames);
+    pi2_logger.AppendAllFilenames(&actual_filenames);
+  }
+
+  ASSERT_THAT(actual_filenames,
+              ::testing::UnorderedElementsAreArray(logfiles_));
+
+  // Strip off the end of one of the files.  Pick one with a lot of data.
+  // For snappy, needs to have enough data to be >1 chunk of compressed data so
+  // that we don't corrupt the entire log part.
+  ::std::string compressed_contents =
+      aos::util::ReadFileToStringOrDie(logfiles_[4]);
+
+  aos::util::WriteStringToFileOrDie(
+      logfiles_[4],
+      compressed_contents.substr(0, compressed_contents.size() - 100));
+
+  const std::vector<LogFile> sorted_parts = SortParts(logfiles_);
+  VerifyParts(sorted_parts);
+}
+
+// Tests that if we remap a remapped channel, it shows up correctly.
+TEST_P(MultinodeLoggerTest, RemapLoggedChannel) {
+  time_converter_.StartEqual();
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(20000));
+  }
+
+  LogReader reader(SortParts(logfiles_));
+
+  // Remap just on pi1.
+  reader.RemapLoggedChannel<aos::timing::Report>(
+      "/aos", configuration::GetNode(reader.configuration(), "pi1"));
+
+  SimulatedEventLoopFactory log_reader_factory(reader.configuration());
+  log_reader_factory.set_send_delay(chrono::microseconds(0));
+
+  std::vector<const Channel *> remapped_channels = reader.RemappedChannels();
+  // Note: An extra channel gets remapped automatically due to a timestamp
+  // channel being LOCAL_LOGGER'd.
+  ASSERT_EQ(remapped_channels.size(), std::get<0>(GetParam()).shared ? 1u : 2u);
+  EXPECT_EQ(remapped_channels[0]->name()->string_view(), "/original/pi1/aos");
+  EXPECT_EQ(remapped_channels[0]->type()->string_view(), "aos.timing.Report");
+  if (!std::get<0>(GetParam()).shared) {
+    EXPECT_EQ(remapped_channels[1]->name()->string_view(),
+              "/original/pi1/aos/remote_timestamps/pi2/pi1/aos/"
+              "aos-message_bridge-Timestamp");
+    EXPECT_EQ(remapped_channels[1]->type()->string_view(),
+              "aos.message_bridge.RemoteMessage");
+  }
+
+  reader.Register(&log_reader_factory);
+
+  const Node *pi1 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi1");
+  const Node *pi2 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi2");
+
+  // Confirm we can read the data on the remapped channel, just for pi1. Nothing
+  // else should have moved.
+  std::unique_ptr<EventLoop> pi1_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi1);
+  pi1_event_loop->SkipTimingReport();
+  std::unique_ptr<EventLoop> full_pi1_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi1);
+  full_pi1_event_loop->SkipTimingReport();
+  std::unique_ptr<EventLoop> pi2_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi2);
+  pi2_event_loop->SkipTimingReport();
+
+  MessageCounter<aos::timing::Report> pi1_timing_report(pi1_event_loop.get(),
+                                                        "/aos");
+  MessageCounter<aos::timing::Report> full_pi1_timing_report(
+      full_pi1_event_loop.get(), "/pi1/aos");
+  MessageCounter<aos::timing::Report> pi1_original_timing_report(
+      pi1_event_loop.get(), "/original/aos");
+  MessageCounter<aos::timing::Report> full_pi1_original_timing_report(
+      full_pi1_event_loop.get(), "/original/pi1/aos");
+  MessageCounter<aos::timing::Report> pi2_timing_report(pi2_event_loop.get(),
+                                                        "/aos");
+
+  log_reader_factory.Run();
+
+  EXPECT_EQ(pi1_timing_report.count(), 0u);
+  EXPECT_EQ(full_pi1_timing_report.count(), 0u);
+  EXPECT_NE(pi1_original_timing_report.count(), 0u);
+  EXPECT_NE(full_pi1_original_timing_report.count(), 0u);
+  EXPECT_NE(pi2_timing_report.count(), 0u);
+
+  reader.Deregister();
+}
+
+// Tests that we can remap a forwarded channel as well.
+TEST_P(MultinodeLoggerTest, RemapForwardedLoggedChannel) {
+  time_converter_.StartEqual();
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(20000));
+  }
+
+  LogReader reader(SortParts(logfiles_));
+
+  reader.RemapLoggedChannel<examples::Ping>("/test");
+
+  SimulatedEventLoopFactory log_reader_factory(reader.configuration());
+  log_reader_factory.set_send_delay(chrono::microseconds(0));
+
+  reader.Register(&log_reader_factory);
+
+  const Node *pi1 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi1");
+  const Node *pi2 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi2");
+
+  // Confirm we can read the data on the remapped channel, just for pi1. Nothing
+  // else should have moved.
+  std::unique_ptr<EventLoop> pi1_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi1);
+  pi1_event_loop->SkipTimingReport();
+  std::unique_ptr<EventLoop> full_pi1_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi1);
+  full_pi1_event_loop->SkipTimingReport();
+  std::unique_ptr<EventLoop> pi2_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi2);
+  pi2_event_loop->SkipTimingReport();
+
+  MessageCounter<examples::Ping> pi1_ping(pi1_event_loop.get(), "/test");
+  MessageCounter<examples::Ping> pi2_ping(pi2_event_loop.get(), "/test");
+  MessageCounter<examples::Ping> pi1_original_ping(pi1_event_loop.get(),
+                                                   "/original/test");
+  MessageCounter<examples::Ping> pi2_original_ping(pi2_event_loop.get(),
+                                                   "/original/test");
+
+  std::unique_ptr<MessageCounter<message_bridge::RemoteMessage>>
+      pi1_original_ping_timestamp;
+  std::unique_ptr<MessageCounter<message_bridge::RemoteMessage>>
+      pi1_ping_timestamp;
+  if (!shared()) {
+    pi1_original_ping_timestamp =
+        std::make_unique<MessageCounter<message_bridge::RemoteMessage>>(
+            pi1_event_loop.get(),
+            "/pi1/aos/remote_timestamps/pi2/original/test/aos-examples-Ping");
+    pi1_ping_timestamp =
+        std::make_unique<MessageCounter<message_bridge::RemoteMessage>>(
+            pi1_event_loop.get(),
+            "/pi1/aos/remote_timestamps/pi2/test/aos-examples-Ping");
+  }
+
+  log_reader_factory.Run();
+
+  EXPECT_EQ(pi1_ping.count(), 0u);
+  EXPECT_EQ(pi2_ping.count(), 0u);
+  EXPECT_NE(pi1_original_ping.count(), 0u);
+  EXPECT_NE(pi2_original_ping.count(), 0u);
+  if (!shared()) {
+    EXPECT_NE(pi1_original_ping_timestamp->count(), 0u);
+    EXPECT_EQ(pi1_ping_timestamp->count(), 0u);
+  }
+
+  reader.Deregister();
+}
+
+// Tests that we observe all the same events in log replay (for a given node)
+// whether we just register an event loop for that node or if we register a full
+// event loop factory.
+TEST_P(MultinodeLoggerTest, SingleNodeReplay) {
+  time_converter_.StartEqual();
+  constexpr chrono::milliseconds kStartupDelay(95);
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(kStartupDelay);
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(20000));
+  }
+
+  LogReader full_reader(SortParts(logfiles_));
+  LogReader single_node_reader(SortParts(logfiles_));
+
+  SimulatedEventLoopFactory full_factory(full_reader.configuration());
+  SimulatedEventLoopFactory single_node_factory(
+      single_node_reader.configuration());
+  single_node_factory.SkipTimingReport();
+  single_node_factory.DisableStatistics();
+  std::unique_ptr<EventLoop> replay_event_loop =
+      single_node_factory.GetNodeEventLoopFactory("pi1")->MakeEventLoop(
+          "log_reader");
+
+  full_reader.Register(&full_factory);
+  single_node_reader.Register(replay_event_loop.get());
+
+  const Node *full_pi1 =
+      configuration::GetNode(full_factory.configuration(), "pi1");
+
+  // Confirm we can read the data on the remapped channel, just for pi1. Nothing
+  // else should have moved.
+  std::unique_ptr<EventLoop> full_event_loop =
+      full_factory.MakeEventLoop("test", full_pi1);
+  full_event_loop->SkipTimingReport();
+  full_event_loop->SkipAosLog();
+  // maps are indexed on channel index.
+  // observed_messages: {channel_index: [(message_sent_time, was_fetched),...]}
+  std::map<size_t, std::vector<std::pair<monotonic_clock::time_point, bool>>>
+      observed_messages;
+  std::map<size_t, std::unique_ptr<RawFetcher>> fetchers;
+  for (size_t ii = 0; ii < full_event_loop->configuration()->channels()->size();
+       ++ii) {
+    const Channel *channel =
+        full_event_loop->configuration()->channels()->Get(ii);
+    // We currently don't support replaying remote timestamp channels in
+    // realtime replay (unless the remote timestamp channel was not NOT_LOGGED,
+    // in which case it gets auto-remapped and replayed on a /original channel).
+    if (channel->name()->string_view().find("remote_timestamp") !=
+            std::string_view::npos &&
+        channel->name()->string_view().find("/original") ==
+            std::string_view::npos) {
+      continue;
+    }
+    if (configuration::ChannelIsReadableOnNode(channel, full_pi1)) {
+      observed_messages[ii] = {};
+      fetchers[ii] = full_event_loop->MakeRawFetcher(channel);
+      full_event_loop->OnRun([ii, &observed_messages, &fetchers]() {
+        if (fetchers[ii]->Fetch()) {
+          observed_messages[ii].push_back(std::make_pair(
+              fetchers[ii]->context().monotonic_event_time, true));
+        }
+      });
+      full_event_loop->MakeRawNoArgWatcher(
+          channel, [ii, &observed_messages](const Context &context) {
+            observed_messages[ii].push_back(
+                std::make_pair(context.monotonic_event_time, false));
+          });
+    }
+  }
+
+  full_factory.Run();
+  fetchers.clear();
+  full_reader.Deregister();
+
+  const Node *single_node_pi1 =
+      configuration::GetNode(single_node_factory.configuration(), "pi1");
+  std::map<size_t, std::unique_ptr<RawFetcher>> single_node_fetchers;
+
+  std::unique_ptr<EventLoop> single_node_event_loop =
+      single_node_factory.MakeEventLoop("test", single_node_pi1);
+  single_node_event_loop->SkipTimingReport();
+  single_node_event_loop->SkipAosLog();
+  for (size_t ii = 0;
+       ii < single_node_event_loop->configuration()->channels()->size(); ++ii) {
+    const Channel *channel =
+        single_node_event_loop->configuration()->channels()->Get(ii);
+    single_node_factory.DisableForwarding(channel);
+    if (configuration::ChannelIsReadableOnNode(channel, single_node_pi1)) {
+      single_node_fetchers[ii] =
+          single_node_event_loop->MakeRawFetcher(channel);
+      single_node_event_loop->OnRun([channel, ii, &single_node_fetchers]() {
+        EXPECT_FALSE(single_node_fetchers[ii]->Fetch())
+            << "Single EventLoop replay doesn't support pre-loading fetchers. "
+            << configuration::StrippedChannelToString(channel);
+      });
+      single_node_event_loop->MakeRawNoArgWatcher(
+          channel, [ii, &observed_messages, channel,
+                    kStartupDelay](const Context &context) {
+            if (observed_messages[ii].empty()) {
+              FAIL() << "Observed extra message at "
+                     << context.monotonic_event_time << " on "
+                     << configuration::StrippedChannelToString(channel);
+              return;
+            }
+            const std::pair<monotonic_clock::time_point, bool> &message =
+                observed_messages[ii].front();
+            if (message.second) {
+              EXPECT_LE(message.first,
+                        context.monotonic_event_time + kStartupDelay)
+                  << "Mismatched message times " << context.monotonic_event_time
+                  << " and " << message.first << " on "
+                  << configuration::StrippedChannelToString(channel);
+            } else {
+              EXPECT_EQ(message.first,
+                        context.monotonic_event_time + kStartupDelay)
+                  << "Mismatched message times " << context.monotonic_event_time
+                  << " and " << message.first << " on "
+                  << configuration::StrippedChannelToString(channel);
+            }
+            observed_messages[ii].erase(observed_messages[ii].begin());
+          });
+    }
+  }
+
+  single_node_factory.Run();
+
+  single_node_fetchers.clear();
+
+  single_node_reader.Deregister();
+
+  for (const auto &pair : observed_messages) {
+    EXPECT_TRUE(pair.second.empty())
+        << "Missed " << pair.second.size() << " messages on "
+        << configuration::StrippedChannelToString(
+               single_node_event_loop->configuration()->channels()->Get(
+                   pair.first));
+  }
+}
+
+// Tests that we properly recreate forwarded timestamps when replaying a log.
+// This should be enough that we can then re-run the logger and get a valid log
+// back.
+TEST_P(MultinodeLoggerTest, MessageHeader) {
+  time_converter_.StartEqual();
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(20000));
+  }
+
+  LogReader reader(SortParts(logfiles_));
+
+  SimulatedEventLoopFactory log_reader_factory(reader.configuration());
+  log_reader_factory.set_send_delay(chrono::microseconds(0));
+
+  // This sends out the fetched messages and advances time to the start of the
+  // log file.
+  reader.Register(&log_reader_factory);
+
+  const Node *pi1 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi1");
+  const Node *pi2 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi2");
+
+  LOG(INFO) << "Start time " << reader.monotonic_start_time(pi1) << " pi1";
+  LOG(INFO) << "Start time " << reader.monotonic_start_time(pi2) << " pi2";
+  LOG(INFO) << "now pi1 "
+            << log_reader_factory.GetNodeEventLoopFactory(pi1)->monotonic_now();
+  LOG(INFO) << "now pi2 "
+            << log_reader_factory.GetNodeEventLoopFactory(pi2)->monotonic_now();
+
+  EXPECT_THAT(reader.LoggedNodes(),
+              ::testing::ElementsAre(
+                  configuration::GetNode(reader.logged_configuration(), pi1),
+                  configuration::GetNode(reader.logged_configuration(), pi2)));
+
+  reader.event_loop_factory()->set_send_delay(chrono::microseconds(0));
+
+  std::unique_ptr<EventLoop> pi1_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi1);
+  std::unique_ptr<EventLoop> pi2_event_loop =
+      log_reader_factory.MakeEventLoop("test", pi2);
+
+  aos::Fetcher<message_bridge::Timestamp> pi1_timestamp_on_pi1_fetcher =
+      pi1_event_loop->MakeFetcher<message_bridge::Timestamp>("/pi1/aos");
+  aos::Fetcher<message_bridge::Timestamp> pi1_timestamp_on_pi2_fetcher =
+      pi2_event_loop->MakeFetcher<message_bridge::Timestamp>("/pi1/aos");
+
+  aos::Fetcher<examples::Ping> ping_on_pi1_fetcher =
+      pi1_event_loop->MakeFetcher<examples::Ping>("/test");
+  aos::Fetcher<examples::Ping> ping_on_pi2_fetcher =
+      pi2_event_loop->MakeFetcher<examples::Ping>("/test");
+
+  aos::Fetcher<message_bridge::Timestamp> pi2_timestamp_on_pi2_fetcher =
+      pi2_event_loop->MakeFetcher<message_bridge::Timestamp>("/pi2/aos");
+  aos::Fetcher<message_bridge::Timestamp> pi2_timestamp_on_pi1_fetcher =
+      pi1_event_loop->MakeFetcher<message_bridge::Timestamp>("/pi2/aos");
+
+  aos::Fetcher<examples::Pong> pong_on_pi2_fetcher =
+      pi2_event_loop->MakeFetcher<examples::Pong>("/test");
+  aos::Fetcher<examples::Pong> pong_on_pi1_fetcher =
+      pi1_event_loop->MakeFetcher<examples::Pong>("/test");
+
+  const size_t pi1_timestamp_channel = configuration::ChannelIndex(
+      pi1_event_loop->configuration(), pi1_timestamp_on_pi1_fetcher.channel());
+  const size_t ping_timestamp_channel = configuration::ChannelIndex(
+      pi2_event_loop->configuration(), ping_on_pi2_fetcher.channel());
+
+  const size_t pi2_timestamp_channel = configuration::ChannelIndex(
+      pi2_event_loop->configuration(), pi2_timestamp_on_pi2_fetcher.channel());
+  const size_t pong_timestamp_channel = configuration::ChannelIndex(
+      pi1_event_loop->configuration(), pong_on_pi1_fetcher.channel());
+
+  const chrono::nanoseconds network_delay = event_loop_factory_.network_delay();
+  const chrono::nanoseconds send_delay = event_loop_factory_.send_delay();
+
+  for (std::pair<int, std::string> channel :
+       shared()
+           ? std::vector<
+                 std::pair<int, std::string>>{{-1,
+                                               "/aos/remote_timestamps/pi2"}}
+           : std::vector<std::pair<int, std::string>>{
+                 {pi1_timestamp_channel,
+                  "/aos/remote_timestamps/pi2/pi1/aos/"
+                  "aos-message_bridge-Timestamp"},
+                 {ping_timestamp_channel,
+                  "/aos/remote_timestamps/pi2/test/aos-examples-Ping"}}) {
+    pi1_event_loop->MakeWatcher(
+        channel.second,
+        [&pi1_event_loop, &pi2_event_loop, pi1_timestamp_channel,
+         ping_timestamp_channel, &pi1_timestamp_on_pi1_fetcher,
+         &pi1_timestamp_on_pi2_fetcher, &ping_on_pi1_fetcher,
+         &ping_on_pi2_fetcher, network_delay, send_delay,
+         channel_index = channel.first](const RemoteMessage &header) {
+          const aos::monotonic_clock::time_point header_monotonic_sent_time(
+              chrono::nanoseconds(header.monotonic_sent_time()));
+          const aos::realtime_clock::time_point header_realtime_sent_time(
+              chrono::nanoseconds(header.realtime_sent_time()));
+          const aos::monotonic_clock::time_point header_monotonic_remote_time(
+              chrono::nanoseconds(header.monotonic_remote_time()));
+          const aos::realtime_clock::time_point header_realtime_remote_time(
+              chrono::nanoseconds(header.realtime_remote_time()));
+
+          if (channel_index != -1) {
+            ASSERT_EQ(channel_index, header.channel_index());
+          }
+
+          const Context *pi1_context = nullptr;
+          const Context *pi2_context = nullptr;
+
+          if (header.channel_index() == pi1_timestamp_channel) {
+            ASSERT_TRUE(pi1_timestamp_on_pi1_fetcher.FetchNext());
+            ASSERT_TRUE(pi1_timestamp_on_pi2_fetcher.FetchNext());
+            pi1_context = &pi1_timestamp_on_pi1_fetcher.context();
+            pi2_context = &pi1_timestamp_on_pi2_fetcher.context();
+          } else if (header.channel_index() == ping_timestamp_channel) {
+            ASSERT_TRUE(ping_on_pi1_fetcher.FetchNext());
+            ASSERT_TRUE(ping_on_pi2_fetcher.FetchNext());
+            pi1_context = &ping_on_pi1_fetcher.context();
+            pi2_context = &ping_on_pi2_fetcher.context();
+          } else {
+            LOG(FATAL) << "Unknown channel " << FlatbufferToJson(&header) << " "
+                       << configuration::CleanedChannelToString(
+                              pi1_event_loop->configuration()->channels()->Get(
+                                  header.channel_index()));
+          }
+
+          ASSERT_TRUE(header.has_boot_uuid());
+          EXPECT_EQ(UUID::FromVector(header.boot_uuid()),
+                    pi2_event_loop->boot_uuid());
+
+          EXPECT_EQ(pi1_context->queue_index, header.remote_queue_index());
+          EXPECT_EQ(pi2_context->remote_queue_index,
+                    header.remote_queue_index());
+          EXPECT_EQ(pi2_context->queue_index, header.queue_index());
+
+          EXPECT_EQ(pi2_context->monotonic_event_time,
+                    header_monotonic_sent_time);
+          EXPECT_EQ(pi2_context->realtime_event_time,
+                    header_realtime_sent_time);
+          EXPECT_EQ(pi2_context->realtime_remote_time,
+                    header_realtime_remote_time);
+          EXPECT_EQ(pi2_context->monotonic_remote_time,
+                    header_monotonic_remote_time);
+
+          EXPECT_EQ(pi1_context->realtime_event_time,
+                    header_realtime_remote_time);
+          EXPECT_EQ(pi1_context->monotonic_event_time,
+                    header_monotonic_remote_time);
+
+          // Time estimation isn't perfect, but we know the clocks were
+          // identical when logged, so we know when this should have come back.
+          // Confirm we got it when we expected.
+          EXPECT_EQ(pi1_event_loop->context().monotonic_event_time,
+                    pi1_context->monotonic_event_time + 2 * network_delay +
+                        send_delay);
+        });
+  }
+  for (std::pair<int, std::string> channel :
+       shared()
+           ? std::vector<
+                 std::pair<int, std::string>>{{-1,
+                                               "/aos/remote_timestamps/pi1"}}
+           : std::vector<std::pair<int, std::string>>{
+                 {pi2_timestamp_channel,
+                  "/aos/remote_timestamps/pi1/pi2/aos/"
+                  "aos-message_bridge-Timestamp"}}) {
+    pi2_event_loop->MakeWatcher(
+        channel.second,
+        [&pi2_event_loop, &pi1_event_loop, pi2_timestamp_channel,
+         pong_timestamp_channel, &pi2_timestamp_on_pi2_fetcher,
+         &pi2_timestamp_on_pi1_fetcher, &pong_on_pi2_fetcher,
+         &pong_on_pi1_fetcher, network_delay, send_delay,
+         channel_index = channel.first](const RemoteMessage &header) {
+          const aos::monotonic_clock::time_point header_monotonic_sent_time(
+              chrono::nanoseconds(header.monotonic_sent_time()));
+          const aos::realtime_clock::time_point header_realtime_sent_time(
+              chrono::nanoseconds(header.realtime_sent_time()));
+          const aos::monotonic_clock::time_point header_monotonic_remote_time(
+              chrono::nanoseconds(header.monotonic_remote_time()));
+          const aos::realtime_clock::time_point header_realtime_remote_time(
+              chrono::nanoseconds(header.realtime_remote_time()));
+
+          if (channel_index != -1) {
+            ASSERT_EQ(channel_index, header.channel_index());
+          }
+
+          const Context *pi2_context = nullptr;
+          const Context *pi1_context = nullptr;
+
+          if (header.channel_index() == pi2_timestamp_channel) {
+            ASSERT_TRUE(pi2_timestamp_on_pi2_fetcher.FetchNext());
+            ASSERT_TRUE(pi2_timestamp_on_pi1_fetcher.FetchNext());
+            pi2_context = &pi2_timestamp_on_pi2_fetcher.context();
+            pi1_context = &pi2_timestamp_on_pi1_fetcher.context();
+          } else if (header.channel_index() == pong_timestamp_channel) {
+            ASSERT_TRUE(pong_on_pi2_fetcher.FetchNext());
+            ASSERT_TRUE(pong_on_pi1_fetcher.FetchNext());
+            pi2_context = &pong_on_pi2_fetcher.context();
+            pi1_context = &pong_on_pi1_fetcher.context();
+          } else {
+            LOG(FATAL) << "Unknown channel " << FlatbufferToJson(&header) << " "
+                       << configuration::CleanedChannelToString(
+                              pi2_event_loop->configuration()->channels()->Get(
+                                  header.channel_index()));
+          }
+
+          ASSERT_TRUE(header.has_boot_uuid());
+          EXPECT_EQ(UUID::FromVector(header.boot_uuid()),
+                    pi1_event_loop->boot_uuid());
+
+          EXPECT_EQ(pi2_context->queue_index, header.remote_queue_index());
+          EXPECT_EQ(pi1_context->remote_queue_index,
+                    header.remote_queue_index());
+          EXPECT_EQ(pi1_context->queue_index, header.queue_index());
+
+          EXPECT_EQ(pi1_context->monotonic_event_time,
+                    header_monotonic_sent_time);
+          EXPECT_EQ(pi1_context->realtime_event_time,
+                    header_realtime_sent_time);
+          EXPECT_EQ(pi1_context->realtime_remote_time,
+                    header_realtime_remote_time);
+          EXPECT_EQ(pi1_context->monotonic_remote_time,
+                    header_monotonic_remote_time);
+
+          EXPECT_EQ(pi2_context->realtime_event_time,
+                    header_realtime_remote_time);
+          EXPECT_EQ(pi2_context->monotonic_event_time,
+                    header_monotonic_remote_time);
+
+          // Time estimation isn't perfect, but we know the clocks were
+          // identical when logged, so we know when this should have come back.
+          // Confirm we got it when we expected.
+          EXPECT_EQ(pi2_event_loop->context().monotonic_event_time,
+                    pi2_context->monotonic_event_time + 2 * network_delay +
+                        send_delay);
+        });
+  }
+
+  // And confirm we can re-create a log again, while checking the contents.
+  {
+    LoggerState pi1_logger = MakeLogger(
+        log_reader_factory.GetNodeEventLoopFactory("pi1"), &log_reader_factory);
+    LoggerState pi2_logger = MakeLogger(
+        log_reader_factory.GetNodeEventLoopFactory("pi2"), &log_reader_factory);
+
+    StartLogger(&pi1_logger, tmp_dir_ + "/relogged1");
+    StartLogger(&pi2_logger, tmp_dir_ + "/relogged2");
+
+    log_reader_factory.Run();
+  }
+
+  reader.Deregister();
+
+  // And verify that we can run the LogReader over the relogged files without
+  // hitting any fatal errors.
+  {
+    LogReader relogged_reader(SortParts(MakeLogFiles(
+        tmp_dir_ + "/relogged1", tmp_dir_ + "/relogged2", 3, 3, true)));
+    relogged_reader.Register();
+
+    relogged_reader.event_loop_factory()->Run();
+  }
+  // And confirm that we can read the logged file using the reader's
+  // configuration.
+  {
+    LogReader relogged_reader(
+        SortParts(MakeLogFiles(tmp_dir_ + "/relogged1", tmp_dir_ + "/relogged2",
+                               3, 3, true)),
+        reader.configuration());
+    relogged_reader.Register();
+
+    relogged_reader.event_loop_factory()->Run();
+  }
+}
+
+// Tests that we properly populate and extract the logger_start time by setting
+// up a clock difference between 2 nodes and looking at the resulting parts.
+TEST_P(MultinodeLoggerTest, LoggerStartTime) {
+  std::vector<std::string> actual_filenames;
+  time_converter_.AddMonotonic(
+      {BootTimestamp::epoch(), BootTimestamp::epoch() + chrono::seconds(1000)});
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(10000));
+
+    pi1_logger.AppendAllFilenames(&actual_filenames);
+    pi2_logger.AppendAllFilenames(&actual_filenames);
+  }
+
+  ASSERT_THAT(actual_filenames,
+              ::testing::UnorderedElementsAreArray(logfiles_));
+
+  for (const LogFile &log_file : SortParts(logfiles_)) {
+    for (const LogParts &log_part : log_file.parts) {
+      if (log_part.node == log_file.logger_node) {
+        EXPECT_EQ(log_part.logger_monotonic_start_time,
+                  aos::monotonic_clock::min_time);
+        EXPECT_EQ(log_part.logger_realtime_start_time,
+                  aos::realtime_clock::min_time);
+      } else {
+        const chrono::seconds offset = log_file.logger_node == "pi1"
+                                           ? -chrono::seconds(1000)
+                                           : chrono::seconds(1000);
+        EXPECT_EQ(log_part.logger_monotonic_start_time,
+                  log_part.monotonic_start_time + offset);
+        EXPECT_EQ(log_part.logger_realtime_start_time,
+                  log_file.realtime_start_time +
+                      (log_part.logger_monotonic_start_time -
+                       log_file.monotonic_start_time));
+      }
+    }
+  }
+}
+
+// Test that renaming the base, renames the folder.
+TEST_P(MultinodeLoggerTest, LoggerRenameFolder) {
+  util::UnlinkRecursive(tmp_dir_ + "/renamefolder");
+  util::UnlinkRecursive(tmp_dir_ + "/new-good");
+  time_converter_.AddMonotonic(
+      {BootTimestamp::epoch(), BootTimestamp::epoch() + chrono::seconds(1000)});
+  logfile_base1_ = tmp_dir_ + "/renamefolder/multi_logfile1";
+  logfile_base2_ = tmp_dir_ + "/renamefolder/multi_logfile2";
+  logfiles_ = MakeLogFiles(logfile_base1_, logfile_base2_);
+  LoggerState pi1_logger = MakeLogger(pi1_);
+  LoggerState pi2_logger = MakeLogger(pi2_);
+
+  StartLogger(&pi1_logger);
+  StartLogger(&pi2_logger);
+
+  event_loop_factory_.RunFor(chrono::milliseconds(10000));
+  logfile_base1_ = tmp_dir_ + "/new-good/multi_logfile1";
+  logfile_base2_ = tmp_dir_ + "/new-good/multi_logfile2";
+  logfiles_ = MakeLogFiles(logfile_base1_, logfile_base2_);
+  ASSERT_TRUE(pi1_logger.logger->RenameLogBase(logfile_base1_));
+  ASSERT_TRUE(pi2_logger.logger->RenameLogBase(logfile_base2_));
+  for (auto &file : logfiles_) {
+    struct stat s;
+    EXPECT_EQ(0, stat(file.c_str(), &s));
+  }
+}
+
+// Test that renaming the file base dies.
+TEST_P(MultinodeLoggerDeathTest, LoggerRenameFile) {
+  time_converter_.AddMonotonic(
+      {BootTimestamp::epoch(), BootTimestamp::epoch() + chrono::seconds(1000)});
+  util::UnlinkRecursive(tmp_dir_ + "/renamefile");
+  logfile_base1_ = tmp_dir_ + "/renamefile/multi_logfile1";
+  logfile_base2_ = tmp_dir_ + "/renamefile/multi_logfile2";
+  logfiles_ = MakeLogFiles(logfile_base1_, logfile_base2_);
+  LoggerState pi1_logger = MakeLogger(pi1_);
+  StartLogger(&pi1_logger);
+  event_loop_factory_.RunFor(chrono::milliseconds(10000));
+  logfile_base1_ = tmp_dir_ + "/new-renamefile/new_multi_logfile1";
+  EXPECT_DEATH({ pi1_logger.logger->RenameLogBase(logfile_base1_); },
+               "Rename of file base from");
+}
+
+// TODO(austin): We can write a test which recreates a logfile and confirms that
+// we get it back.  That is the ultimate test.
+
+// Tests that we properly recreate forwarded timestamps when replaying a log.
+// This should be enough that we can then re-run the logger and get a valid log
+// back.
+TEST_P(MultinodeLoggerTest, RemoteReboot) {
+  std::vector<std::string> actual_filenames;
+
+  const UUID pi1_boot0 = UUID::Random();
+  const UUID pi2_boot0 = UUID::Random();
+  const UUID pi2_boot1 = UUID::Random();
+  {
+    CHECK_EQ(pi1_index_, 0u);
+    CHECK_EQ(pi2_index_, 1u);
+
+    time_converter_.set_boot_uuid(pi1_index_, 0, pi1_boot0);
+    time_converter_.set_boot_uuid(pi2_index_, 0, pi2_boot0);
+    time_converter_.set_boot_uuid(pi2_index_, 1, pi2_boot1);
+
+    time_converter_.AddNextTimestamp(
+        distributed_clock::epoch(),
+        {BootTimestamp::epoch(), BootTimestamp::epoch()});
+    const chrono::nanoseconds reboot_time = chrono::milliseconds(10100);
+    time_converter_.AddNextTimestamp(
+        distributed_clock::epoch() + reboot_time,
+        {BootTimestamp::epoch() + reboot_time,
+         BootTimestamp{
+             .boot = 1,
+             .time = monotonic_clock::epoch() + chrono::milliseconds(1323)}});
+  }
+
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+    EXPECT_EQ(event_loop_factory_.GetNodeEventLoopFactory("pi1")->boot_uuid(),
+              pi1_boot0);
+    EXPECT_EQ(event_loop_factory_.GetNodeEventLoopFactory("pi2")->boot_uuid(),
+              pi2_boot0);
+
+    StartLogger(&pi1_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(10000));
+
+    VLOG(1) << "Reboot now!";
+
+    event_loop_factory_.RunFor(chrono::milliseconds(20000));
+    EXPECT_EQ(event_loop_factory_.GetNodeEventLoopFactory("pi1")->boot_uuid(),
+              pi1_boot0);
+    EXPECT_EQ(event_loop_factory_.GetNodeEventLoopFactory("pi2")->boot_uuid(),
+              pi2_boot1);
+
+    pi1_logger.AppendAllFilenames(&actual_filenames);
+  }
+
+  std::sort(actual_filenames.begin(), actual_filenames.end());
+  std::sort(pi1_reboot_logfiles_.begin(), pi1_reboot_logfiles_.end());
+  ASSERT_THAT(actual_filenames,
+              ::testing::UnorderedElementsAreArray(pi1_reboot_logfiles_));
+
+  // Confirm that our new oldest timestamps properly update as we reboot and
+  // rotate.
+  for (const std::string &file : pi1_reboot_logfiles_) {
+    std::optional<SizePrefixedFlatbufferVector<LogFileHeader>> log_header =
+        ReadHeader(file);
+    CHECK(log_header);
+    if (log_header->message().has_configuration()) {
+      continue;
+    }
+
+    const monotonic_clock::time_point monotonic_start_time =
+        monotonic_clock::time_point(
+            chrono::nanoseconds(log_header->message().monotonic_start_time()));
+    const UUID source_node_boot_uuid = UUID::FromString(
+        log_header->message().source_node_boot_uuid()->string_view());
+
+    if (log_header->message().node()->name()->string_view() != "pi1") {
+      // The remote message channel should rotate later and have more parts.
+      // This only is true on the log files with shared remote messages.
+      //
+      // TODO(austin): I'm not the most thrilled with this test pattern...  It
+      // feels brittle in a different way.
+      if (file.find("aos.message_bridge.RemoteMessage") == std::string::npos ||
+          !shared()) {
+        switch (log_header->message().parts_index()) {
+          case 0:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot0);
+            EXPECT_EQ(monotonic_start_time, monotonic_clock::min_time);
+            break;
+          case 1:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot0);
+            ASSERT_EQ(monotonic_start_time,
+                      monotonic_clock::epoch() + chrono::seconds(1));
+            break;
+          case 2:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot1);
+            EXPECT_EQ(monotonic_start_time, monotonic_clock::min_time) << file;
+            break;
+          case 3:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot1);
+            ASSERT_EQ(monotonic_start_time, monotonic_clock::epoch() +
+                                                chrono::nanoseconds(2322999462))
+                << " on " << file;
+            break;
+          default:
+            FAIL();
+            break;
+        }
+      } else {
+        switch (log_header->message().parts_index()) {
+          case 0:
+          case 1:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot0);
+            EXPECT_EQ(monotonic_start_time, monotonic_clock::min_time);
+            break;
+          case 2:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot0);
+            ASSERT_EQ(monotonic_start_time,
+                      monotonic_clock::epoch() + chrono::seconds(1));
+            break;
+          case 3:
+          case 4:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot1);
+            EXPECT_EQ(monotonic_start_time, monotonic_clock::min_time) << file;
+            break;
+          case 5:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot1);
+            ASSERT_EQ(monotonic_start_time, monotonic_clock::epoch() +
+                                                chrono::nanoseconds(2322999462))
+                << " on " << file;
+            break;
+          default:
+            FAIL();
+            break;
+        }
+      }
+      continue;
+    }
+    SCOPED_TRACE(file);
+    SCOPED_TRACE(aos::FlatbufferToJson(
+        *log_header, {.multi_line = true, .max_vector_size = 100}));
+    ASSERT_TRUE(log_header->message().has_oldest_remote_monotonic_timestamps());
+    ASSERT_EQ(
+        log_header->message().oldest_remote_monotonic_timestamps()->size(), 2u);
+    EXPECT_EQ(
+        log_header->message().oldest_remote_monotonic_timestamps()->Get(0),
+        monotonic_clock::max_time.time_since_epoch().count());
+    ASSERT_TRUE(log_header->message().has_oldest_local_monotonic_timestamps());
+    ASSERT_EQ(log_header->message().oldest_local_monotonic_timestamps()->size(),
+              2u);
+    EXPECT_EQ(log_header->message().oldest_local_monotonic_timestamps()->Get(0),
+              monotonic_clock::max_time.time_since_epoch().count());
+    ASSERT_TRUE(log_header->message()
+                    .has_oldest_remote_unreliable_monotonic_timestamps());
+    ASSERT_EQ(log_header->message()
+                  .oldest_remote_unreliable_monotonic_timestamps()
+                  ->size(),
+              2u);
+    EXPECT_EQ(log_header->message()
+                  .oldest_remote_unreliable_monotonic_timestamps()
+                  ->Get(0),
+              monotonic_clock::max_time.time_since_epoch().count());
+    ASSERT_TRUE(log_header->message()
+                    .has_oldest_local_unreliable_monotonic_timestamps());
+    ASSERT_EQ(log_header->message()
+                  .oldest_local_unreliable_monotonic_timestamps()
+                  ->size(),
+              2u);
+    EXPECT_EQ(log_header->message()
+                  .oldest_local_unreliable_monotonic_timestamps()
+                  ->Get(0),
+              monotonic_clock::max_time.time_since_epoch().count());
+
+    const monotonic_clock::time_point oldest_remote_monotonic_timestamps =
+        monotonic_clock::time_point(chrono::nanoseconds(
+            log_header->message().oldest_remote_monotonic_timestamps()->Get(
+                1)));
+    const monotonic_clock::time_point oldest_local_monotonic_timestamps =
+        monotonic_clock::time_point(chrono::nanoseconds(
+            log_header->message().oldest_local_monotonic_timestamps()->Get(1)));
+    const monotonic_clock::time_point
+        oldest_remote_unreliable_monotonic_timestamps =
+            monotonic_clock::time_point(chrono::nanoseconds(
+                log_header->message()
+                    .oldest_remote_unreliable_monotonic_timestamps()
+                    ->Get(1)));
+    const monotonic_clock::time_point
+        oldest_local_unreliable_monotonic_timestamps =
+            monotonic_clock::time_point(chrono::nanoseconds(
+                log_header->message()
+                    .oldest_local_unreliable_monotonic_timestamps()
+                    ->Get(1)));
+    const monotonic_clock::time_point
+        oldest_remote_reliable_monotonic_timestamps =
+            monotonic_clock::time_point(chrono::nanoseconds(
+                log_header->message()
+                    .oldest_remote_reliable_monotonic_timestamps()
+                    ->Get(1)));
+    const monotonic_clock::time_point
+        oldest_local_reliable_monotonic_timestamps =
+            monotonic_clock::time_point(chrono::nanoseconds(
+                log_header->message()
+                    .oldest_local_reliable_monotonic_timestamps()
+                    ->Get(1)));
+    const monotonic_clock::time_point
+        oldest_logger_remote_unreliable_monotonic_timestamps =
+            monotonic_clock::time_point(chrono::nanoseconds(
+                log_header->message()
+                    .oldest_logger_remote_unreliable_monotonic_timestamps()
+                    ->Get(0)));
+    const monotonic_clock::time_point
+        oldest_logger_local_unreliable_monotonic_timestamps =
+            monotonic_clock::time_point(chrono::nanoseconds(
+                log_header->message()
+                    .oldest_logger_local_unreliable_monotonic_timestamps()
+                    ->Get(0)));
+    EXPECT_EQ(oldest_logger_remote_unreliable_monotonic_timestamps,
+              monotonic_clock::max_time);
+    EXPECT_EQ(oldest_logger_local_unreliable_monotonic_timestamps,
+              monotonic_clock::max_time);
+    switch (log_header->message().parts_index()) {
+      case 0:
+        EXPECT_EQ(oldest_remote_monotonic_timestamps,
+                  monotonic_clock::max_time);
+        EXPECT_EQ(oldest_local_monotonic_timestamps, monotonic_clock::max_time);
+        EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::max_time);
+        EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::max_time);
+        EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                  monotonic_clock::max_time);
+        EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                  monotonic_clock::max_time);
+        break;
+      case 1:
+        EXPECT_EQ(oldest_remote_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(90200)));
+        EXPECT_EQ(oldest_local_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(90350)));
+        EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(90200)));
+        EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(90350)));
+        EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                  monotonic_clock::max_time);
+        EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                  monotonic_clock::max_time);
+        break;
+      case 2:
+        EXPECT_EQ(oldest_remote_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(90200)))
+            << file;
+        EXPECT_EQ(oldest_local_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(90350)))
+            << file;
+        EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(90200)))
+            << file;
+        EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(90350)))
+            << file;
+        EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(100000)))
+            << file;
+        EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(100150)))
+            << file;
+        break;
+      case 3:
+        EXPECT_EQ(oldest_remote_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::milliseconds(1323) +
+                                              chrono::microseconds(200)));
+        EXPECT_EQ(oldest_local_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(10100350)));
+        EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::milliseconds(1323) +
+                                              chrono::microseconds(200)));
+        EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(10100350)));
+        EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                  monotonic_clock::max_time)
+            << file;
+        EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                  monotonic_clock::max_time)
+            << file;
+        break;
+      case 4:
+        EXPECT_EQ(oldest_remote_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::milliseconds(1323) +
+                                              chrono::microseconds(200)));
+        EXPECT_EQ(oldest_local_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(10100350)));
+        EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::milliseconds(1323) +
+                                              chrono::microseconds(200)));
+        EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(10100350)));
+        EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(1423000)))
+            << file;
+        EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                  monotonic_clock::time_point(chrono::microseconds(10200150)))
+            << file;
+        break;
+      default:
+        FAIL();
+        break;
+    }
+  }
+
+  // Confirm that we refuse to replay logs with missing boot uuids.
+  {
+    LogReader reader(SortParts(pi1_reboot_logfiles_));
+
+    SimulatedEventLoopFactory log_reader_factory(reader.configuration());
+    log_reader_factory.set_send_delay(chrono::microseconds(0));
+
+    // This sends out the fetched messages and advances time to the start of
+    // the log file.
+    reader.Register(&log_reader_factory);
+
+    log_reader_factory.Run();
+
+    reader.Deregister();
+  }
+}
+
+// Tests that we can sort a log which only has timestamps from the remote
+// because the local message_bridge_client failed to connect.
+TEST_P(MultinodeLoggerTest, RemoteRebootOnlyTimestamps) {
+  const UUID pi1_boot0 = UUID::Random();
+  const UUID pi2_boot0 = UUID::Random();
+  const UUID pi2_boot1 = UUID::Random();
+  {
+    CHECK_EQ(pi1_index_, 0u);
+    CHECK_EQ(pi2_index_, 1u);
+
+    time_converter_.set_boot_uuid(pi1_index_, 0, pi1_boot0);
+    time_converter_.set_boot_uuid(pi2_index_, 0, pi2_boot0);
+    time_converter_.set_boot_uuid(pi2_index_, 1, pi2_boot1);
+
+    time_converter_.AddNextTimestamp(
+        distributed_clock::epoch(),
+        {BootTimestamp::epoch(), BootTimestamp::epoch()});
+    const chrono::nanoseconds reboot_time = chrono::milliseconds(10100);
+    time_converter_.AddNextTimestamp(
+        distributed_clock::epoch() + reboot_time,
+        {BootTimestamp::epoch() + reboot_time,
+         BootTimestamp{
+             .boot = 1,
+             .time = monotonic_clock::epoch() + chrono::milliseconds(1323)}});
+  }
+  pi2_->Disconnect(pi1_->node());
+
+  std::vector<std::string> filenames;
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+    EXPECT_EQ(event_loop_factory_.GetNodeEventLoopFactory("pi1")->boot_uuid(),
+              pi1_boot0);
+    EXPECT_EQ(event_loop_factory_.GetNodeEventLoopFactory("pi2")->boot_uuid(),
+              pi2_boot0);
+
+    StartLogger(&pi1_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(10000));
+
+    VLOG(1) << "Reboot now!";
+
+    event_loop_factory_.RunFor(chrono::milliseconds(20000));
+    EXPECT_EQ(event_loop_factory_.GetNodeEventLoopFactory("pi1")->boot_uuid(),
+              pi1_boot0);
+    EXPECT_EQ(event_loop_factory_.GetNodeEventLoopFactory("pi2")->boot_uuid(),
+              pi2_boot1);
+    pi1_logger.AppendAllFilenames(&filenames);
+  }
+
+  std::sort(filenames.begin(), filenames.end());
+
+  // Confirm that our new oldest timestamps properly update as we reboot and
+  // rotate.
+  size_t timestamp_file_count = 0;
+  for (const std::string &file : filenames) {
+    std::optional<SizePrefixedFlatbufferVector<LogFileHeader>> log_header =
+        ReadHeader(file);
+    CHECK(log_header);
+
+    if (log_header->message().has_configuration()) {
+      continue;
+    }
+
+    const monotonic_clock::time_point monotonic_start_time =
+        monotonic_clock::time_point(
+            chrono::nanoseconds(log_header->message().monotonic_start_time()));
+    const UUID source_node_boot_uuid = UUID::FromString(
+        log_header->message().source_node_boot_uuid()->string_view());
+
+    ASSERT_TRUE(log_header->message().has_oldest_remote_monotonic_timestamps());
+    ASSERT_EQ(
+        log_header->message().oldest_remote_monotonic_timestamps()->size(), 2u);
+    ASSERT_TRUE(log_header->message().has_oldest_local_monotonic_timestamps());
+    ASSERT_EQ(log_header->message().oldest_local_monotonic_timestamps()->size(),
+              2u);
+    ASSERT_TRUE(log_header->message()
+                    .has_oldest_remote_unreliable_monotonic_timestamps());
+    ASSERT_EQ(log_header->message()
+                  .oldest_remote_unreliable_monotonic_timestamps()
+                  ->size(),
+              2u);
+    ASSERT_TRUE(log_header->message()
+                    .has_oldest_local_unreliable_monotonic_timestamps());
+    ASSERT_EQ(log_header->message()
+                  .oldest_local_unreliable_monotonic_timestamps()
+                  ->size(),
+              2u);
+    ASSERT_TRUE(log_header->message()
+                    .has_oldest_remote_reliable_monotonic_timestamps());
+    ASSERT_EQ(log_header->message()
+                  .oldest_remote_reliable_monotonic_timestamps()
+                  ->size(),
+              2u);
+    ASSERT_TRUE(
+        log_header->message().has_oldest_local_reliable_monotonic_timestamps());
+    ASSERT_EQ(log_header->message()
+                  .oldest_local_reliable_monotonic_timestamps()
+                  ->size(),
+              2u);
+
+    ASSERT_TRUE(
+        log_header->message()
+            .has_oldest_logger_remote_unreliable_monotonic_timestamps());
+    ASSERT_EQ(log_header->message()
+                  .oldest_logger_remote_unreliable_monotonic_timestamps()
+                  ->size(),
+              2u);
+    ASSERT_TRUE(log_header->message()
+                    .has_oldest_logger_local_unreliable_monotonic_timestamps());
+    ASSERT_EQ(log_header->message()
+                  .oldest_logger_local_unreliable_monotonic_timestamps()
+                  ->size(),
+              2u);
+
+    if (log_header->message().node()->name()->string_view() != "pi1") {
+      ASSERT_TRUE(file.find("aos.message_bridge.RemoteMessage") !=
+                  std::string::npos);
+
+      const std::optional<SizePrefixedFlatbufferVector<MessageHeader>> msg =
+          ReadNthMessage(file, 0);
+      CHECK(msg);
+
+      EXPECT_TRUE(msg->message().has_monotonic_sent_time());
+      EXPECT_TRUE(msg->message().has_monotonic_remote_time());
+
+      const monotonic_clock::time_point
+          expected_oldest_local_monotonic_timestamps(
+              chrono::nanoseconds(msg->message().monotonic_sent_time()));
+      const monotonic_clock::time_point
+          expected_oldest_remote_monotonic_timestamps(
+              chrono::nanoseconds(msg->message().monotonic_remote_time()));
+      const monotonic_clock::time_point
+          expected_oldest_timestamp_monotonic_timestamps(
+              chrono::nanoseconds(msg->message().monotonic_timestamp_time()));
+
+      EXPECT_NE(expected_oldest_local_monotonic_timestamps,
+                monotonic_clock::min_time);
+      EXPECT_NE(expected_oldest_remote_monotonic_timestamps,
+                monotonic_clock::min_time);
+      EXPECT_NE(expected_oldest_timestamp_monotonic_timestamps,
+                monotonic_clock::min_time);
+
+      ++timestamp_file_count;
+      // Since the log file is from the perspective of the other node,
+      const monotonic_clock::time_point oldest_remote_monotonic_timestamps =
+          monotonic_clock::time_point(chrono::nanoseconds(
+              log_header->message().oldest_remote_monotonic_timestamps()->Get(
+                  0)));
+      const monotonic_clock::time_point oldest_local_monotonic_timestamps =
+          monotonic_clock::time_point(chrono::nanoseconds(
+              log_header->message().oldest_local_monotonic_timestamps()->Get(
+                  0)));
+      const monotonic_clock::time_point
+          oldest_remote_unreliable_monotonic_timestamps =
+              monotonic_clock::time_point(chrono::nanoseconds(
+                  log_header->message()
+                      .oldest_remote_unreliable_monotonic_timestamps()
+                      ->Get(0)));
+      const monotonic_clock::time_point
+          oldest_local_unreliable_monotonic_timestamps =
+              monotonic_clock::time_point(chrono::nanoseconds(
+                  log_header->message()
+                      .oldest_local_unreliable_monotonic_timestamps()
+                      ->Get(0)));
+      const monotonic_clock::time_point
+          oldest_remote_reliable_monotonic_timestamps =
+              monotonic_clock::time_point(chrono::nanoseconds(
+                  log_header->message()
+                      .oldest_remote_reliable_monotonic_timestamps()
+                      ->Get(0)));
+      const monotonic_clock::time_point
+          oldest_local_reliable_monotonic_timestamps =
+              monotonic_clock::time_point(chrono::nanoseconds(
+                  log_header->message()
+                      .oldest_local_reliable_monotonic_timestamps()
+                      ->Get(0)));
+      const monotonic_clock::time_point
+          oldest_logger_remote_unreliable_monotonic_timestamps =
+              monotonic_clock::time_point(chrono::nanoseconds(
+                  log_header->message()
+                      .oldest_logger_remote_unreliable_monotonic_timestamps()
+                      ->Get(1)));
+      const monotonic_clock::time_point
+          oldest_logger_local_unreliable_monotonic_timestamps =
+              monotonic_clock::time_point(chrono::nanoseconds(
+                  log_header->message()
+                      .oldest_logger_local_unreliable_monotonic_timestamps()
+                      ->Get(1)));
+
+      const Channel *channel =
+          event_loop_factory_.configuration()->channels()->Get(
+              msg->message().channel_index());
+      const Connection *connection = configuration::ConnectionToNode(
+          channel, configuration::GetNode(
+                       event_loop_factory_.configuration(),
+                       log_header->message().node()->name()->string_view()));
+
+      const bool reliable = connection->time_to_live() == 0;
+
+      SCOPED_TRACE(file);
+      SCOPED_TRACE(aos::FlatbufferToJson(
+          *log_header, {.multi_line = true, .max_vector_size = 100}));
+
+      if (shared()) {
+        // Confirm that the oldest timestamps match what we expect.  Based on
+        // what we are doing, we know that the oldest time is the first
+        // message's time.
+        //
+        // This makes the test robust to both the split and combined config
+        // tests.
+        switch (log_header->message().parts_index()) {
+          case 0:
+            EXPECT_EQ(oldest_remote_monotonic_timestamps,
+                      expected_oldest_remote_monotonic_timestamps);
+            EXPECT_EQ(oldest_local_monotonic_timestamps,
+                      expected_oldest_local_monotonic_timestamps);
+            EXPECT_EQ(oldest_logger_remote_unreliable_monotonic_timestamps,
+                      expected_oldest_local_monotonic_timestamps)
+                << file;
+            EXPECT_EQ(oldest_logger_local_unreliable_monotonic_timestamps,
+                      expected_oldest_timestamp_monotonic_timestamps)
+                << file;
+
+            if (reliable) {
+              EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                        expected_oldest_remote_monotonic_timestamps);
+              EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                        expected_oldest_local_monotonic_timestamps);
+              EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+            } else {
+              EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                        expected_oldest_remote_monotonic_timestamps);
+              EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                        expected_oldest_local_monotonic_timestamps);
+            }
+            break;
+          case 1:
+            EXPECT_EQ(oldest_remote_monotonic_timestamps,
+                      monotonic_clock::epoch() + chrono::nanoseconds(90000000));
+            EXPECT_EQ(oldest_local_monotonic_timestamps,
+                      monotonic_clock::epoch() + chrono::nanoseconds(90150000));
+            EXPECT_EQ(oldest_logger_remote_unreliable_monotonic_timestamps,
+                      monotonic_clock::epoch() + chrono::nanoseconds(90150000));
+            EXPECT_EQ(oldest_logger_local_unreliable_monotonic_timestamps,
+                      monotonic_clock::epoch() + chrono::nanoseconds(90250000));
+            if (reliable) {
+              EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                        expected_oldest_remote_monotonic_timestamps);
+              EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                        expected_oldest_local_monotonic_timestamps);
+              EXPECT_EQ(
+                  oldest_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::epoch() + chrono::nanoseconds(90000000));
+              EXPECT_EQ(
+                  oldest_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::epoch() + chrono::nanoseconds(90150000));
+            } else {
+              EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                        expected_oldest_remote_monotonic_timestamps);
+              EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                        expected_oldest_local_monotonic_timestamps);
+            }
+            break;
+          case 2:
+            EXPECT_EQ(
+                oldest_remote_monotonic_timestamps,
+                monotonic_clock::epoch() + chrono::nanoseconds(10000000000));
+            EXPECT_EQ(
+                oldest_local_monotonic_timestamps,
+                monotonic_clock::epoch() + chrono::nanoseconds(1323100000));
+            EXPECT_EQ(oldest_logger_remote_unreliable_monotonic_timestamps,
+                      expected_oldest_local_monotonic_timestamps)
+                << file;
+            EXPECT_EQ(oldest_logger_local_unreliable_monotonic_timestamps,
+                      expected_oldest_timestamp_monotonic_timestamps)
+                << file;
+            if (reliable) {
+              EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                        expected_oldest_remote_monotonic_timestamps);
+              EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                        expected_oldest_local_monotonic_timestamps);
+              EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+            } else {
+              EXPECT_EQ(oldest_remote_reliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(oldest_local_reliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                        expected_oldest_remote_monotonic_timestamps);
+              EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                        expected_oldest_local_monotonic_timestamps);
+            }
+            break;
+
+          case 3:
+            EXPECT_EQ(
+                oldest_remote_monotonic_timestamps,
+                monotonic_clock::epoch() + chrono::nanoseconds(10000000000));
+            EXPECT_EQ(
+                oldest_local_monotonic_timestamps,
+                monotonic_clock::epoch() + chrono::nanoseconds(1323100000));
+            EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                      expected_oldest_remote_monotonic_timestamps);
+            EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                      expected_oldest_local_monotonic_timestamps);
+            EXPECT_EQ(
+                oldest_logger_remote_unreliable_monotonic_timestamps,
+                monotonic_clock::epoch() + chrono::nanoseconds(1323100000));
+            EXPECT_EQ(
+                oldest_logger_local_unreliable_monotonic_timestamps,
+                monotonic_clock::epoch() + chrono::nanoseconds(10100200000));
+            break;
+          default:
+            FAIL();
+            break;
+        }
+
+        switch (log_header->message().parts_index()) {
+          case 0:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot0);
+            EXPECT_EQ(monotonic_start_time, monotonic_clock::min_time);
+            break;
+          case 1:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot0);
+            EXPECT_EQ(monotonic_start_time, monotonic_clock::min_time);
+            break;
+          case 2:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot1);
+            EXPECT_EQ(monotonic_start_time, monotonic_clock::min_time);
+            break;
+          case 3:
+            if (shared()) {
+              EXPECT_EQ(source_node_boot_uuid, pi2_boot1);
+              EXPECT_EQ(monotonic_start_time, monotonic_clock::min_time);
+              break;
+            }
+            [[fallthrough]];
+          default:
+            FAIL();
+            break;
+        }
+      } else {
+        switch (log_header->message().parts_index()) {
+          case 0:
+            if (reliable) {
+              EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(
+                  oldest_logger_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::epoch() + chrono::nanoseconds(100150000))
+                  << file;
+              EXPECT_EQ(
+                  oldest_logger_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::epoch() + chrono::nanoseconds(100250000))
+                  << file;
+            } else {
+              EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                        expected_oldest_remote_monotonic_timestamps);
+              EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                        expected_oldest_local_monotonic_timestamps);
+              EXPECT_EQ(
+                  oldest_logger_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::epoch() + chrono::nanoseconds(90150000))
+                  << file;
+              EXPECT_EQ(
+                  oldest_logger_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::epoch() + chrono::nanoseconds(90250000))
+                  << file;
+            }
+            break;
+          case 1:
+            if (reliable) {
+              EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                        monotonic_clock::max_time);
+              EXPECT_EQ(
+                  oldest_logger_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::epoch() + chrono::nanoseconds(1323100000));
+              EXPECT_EQ(
+                  oldest_logger_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::epoch() + chrono::nanoseconds(10100200000));
+            } else {
+              EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                        expected_oldest_remote_monotonic_timestamps);
+              EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                        expected_oldest_local_monotonic_timestamps);
+              EXPECT_EQ(
+                  oldest_logger_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::epoch() + chrono::nanoseconds(1323150000));
+              EXPECT_EQ(
+                  oldest_logger_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::epoch() + chrono::nanoseconds(10100250000));
+            }
+            break;
+          default:
+            FAIL();
+            break;
+        }
+
+        switch (log_header->message().parts_index()) {
+          case 0:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot0);
+            EXPECT_EQ(monotonic_start_time, monotonic_clock::min_time);
+            break;
+          case 1:
+            EXPECT_EQ(source_node_boot_uuid, pi2_boot1);
+            EXPECT_EQ(monotonic_start_time, monotonic_clock::min_time);
+            break;
+          default:
+            FAIL();
+            break;
+        }
+      }
+
+      continue;
+    }
+    EXPECT_EQ(
+        log_header->message().oldest_remote_monotonic_timestamps()->Get(0),
+        monotonic_clock::max_time.time_since_epoch().count());
+    EXPECT_EQ(log_header->message().oldest_local_monotonic_timestamps()->Get(0),
+              monotonic_clock::max_time.time_since_epoch().count());
+    EXPECT_EQ(log_header->message()
+                  .oldest_remote_unreliable_monotonic_timestamps()
+                  ->Get(0),
+              monotonic_clock::max_time.time_since_epoch().count());
+    EXPECT_EQ(log_header->message()
+                  .oldest_local_unreliable_monotonic_timestamps()
+                  ->Get(0),
+              monotonic_clock::max_time.time_since_epoch().count());
+
+    const monotonic_clock::time_point oldest_remote_monotonic_timestamps =
+        monotonic_clock::time_point(chrono::nanoseconds(
+            log_header->message().oldest_remote_monotonic_timestamps()->Get(
+                1)));
+    const monotonic_clock::time_point oldest_local_monotonic_timestamps =
+        monotonic_clock::time_point(chrono::nanoseconds(
+            log_header->message().oldest_local_monotonic_timestamps()->Get(1)));
+    const monotonic_clock::time_point
+        oldest_remote_unreliable_monotonic_timestamps =
+            monotonic_clock::time_point(chrono::nanoseconds(
+                log_header->message()
+                    .oldest_remote_unreliable_monotonic_timestamps()
+                    ->Get(1)));
+    const monotonic_clock::time_point
+        oldest_local_unreliable_monotonic_timestamps =
+            monotonic_clock::time_point(chrono::nanoseconds(
+                log_header->message()
+                    .oldest_local_unreliable_monotonic_timestamps()
+                    ->Get(1)));
+    switch (log_header->message().parts_index()) {
+      case 0:
+        EXPECT_EQ(oldest_remote_monotonic_timestamps,
+                  monotonic_clock::max_time);
+        EXPECT_EQ(oldest_local_monotonic_timestamps, monotonic_clock::max_time);
+        EXPECT_EQ(oldest_remote_unreliable_monotonic_timestamps,
+                  monotonic_clock::max_time);
+        EXPECT_EQ(oldest_local_unreliable_monotonic_timestamps,
+                  monotonic_clock::max_time);
+        break;
+      default:
+        FAIL();
+        break;
+    }
+  }
+
+  if (shared()) {
+    EXPECT_EQ(timestamp_file_count, 4u);
+  } else {
+    EXPECT_EQ(timestamp_file_count, 4u);
+  }
+
+  // Confirm that we can actually sort the resulting log and read it.
+  {
+    LogReader reader(SortParts(filenames));
+
+    SimulatedEventLoopFactory log_reader_factory(reader.configuration());
+    log_reader_factory.set_send_delay(chrono::microseconds(0));
+
+    // This sends out the fetched messages and advances time to the start of
+    // the log file.
+    reader.Register(&log_reader_factory);
+
+    log_reader_factory.Run();
+
+    reader.Deregister();
+  }
+}
+
+// Tests that we properly handle one direction of message_bridge being
+// unavailable.
+TEST_P(MultinodeLoggerTest, OneDirectionWithNegativeSlope) {
+  pi1_->Disconnect(pi2_->node());
+  time_converter_.AddMonotonic(
+      {BootTimestamp::epoch(), BootTimestamp::epoch() + chrono::seconds(1000)});
+
+  time_converter_.AddMonotonic(
+      {chrono::milliseconds(10000),
+       chrono::milliseconds(10000) - chrono::milliseconds(1)});
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(10000));
+  }
+
+  // Confirm that we can parse the result.  LogReader has enough internal CHECKs
+  // to confirm the right thing happened.
+  ConfirmReadable(pi1_single_direction_logfiles_);
+}
+
+// Tests that we properly handle one direction of message_bridge being
+// unavailable.
+TEST_P(MultinodeLoggerTest, OneDirectionWithPositiveSlope) {
+  pi1_->Disconnect(pi2_->node());
+  time_converter_.AddMonotonic(
+      {BootTimestamp::epoch(), BootTimestamp::epoch() + chrono::seconds(500)});
+
+  time_converter_.AddMonotonic(
+      {chrono::milliseconds(10000),
+       chrono::milliseconds(10000) + chrono::milliseconds(1)});
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(10000));
+  }
+
+  // Confirm that we can parse the result.  LogReader has enough internal CHECKs
+  // to confirm the right thing happened.
+  ConfirmReadable(pi1_single_direction_logfiles_);
+}
+
+// Tests that we explode if someone passes in a part file twice with a better
+// error than an out of order error.
+TEST_P(MultinodeLoggerTest, DuplicateLogFiles) {
+  time_converter_.AddMonotonic(
+      {BootTimestamp::epoch(), BootTimestamp::epoch() + chrono::seconds(1000)});
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(10000));
+  }
+
+  std::vector<std::string> duplicates;
+  for (const std::string &f : pi1_single_direction_logfiles_) {
+    duplicates.emplace_back(f);
+    duplicates.emplace_back(f);
+  }
+  EXPECT_DEATH({ SortParts(duplicates); }, "Found duplicate parts in");
+}
+
+// Tests that we explode if someone loses a part out of the middle of a log.
+TEST_P(MultinodeLoggerTest, MissingPartsFromMiddle) {
+  time_converter_.AddMonotonic(
+      {BootTimestamp::epoch(), BootTimestamp::epoch() + chrono::seconds(1000)});
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+    aos::monotonic_clock::time_point last_rotation_time =
+        pi1_logger.event_loop->monotonic_now();
+    pi1_logger.logger->set_on_logged_period([&] {
+      const auto now = pi1_logger.event_loop->monotonic_now();
+      if (now > last_rotation_time + std::chrono::seconds(5)) {
+        pi1_logger.logger->Rotate();
+        last_rotation_time = now;
+      }
+    });
+
+    event_loop_factory_.RunFor(chrono::milliseconds(10000));
+  }
+
+  std::vector<std::string> missing_parts;
+
+  missing_parts.emplace_back(logfile_base1_ + "_pi1_data.part0" + Extension());
+  missing_parts.emplace_back(logfile_base1_ + "_pi1_data.part2" + Extension());
+  missing_parts.emplace_back(absl::StrCat(
+      logfile_base1_, "_", std::get<0>(GetParam()).sha256, Extension()));
+
+  EXPECT_DEATH({ SortParts(missing_parts); },
+               "Broken log, missing part files between");
+}
+
+// Tests that we properly handle a dead node.  Do this by just disconnecting it
+// and only using one nodes of logs.
+TEST_P(MultinodeLoggerTest, DeadNode) {
+  pi1_->Disconnect(pi2_->node());
+  pi2_->Disconnect(pi1_->node());
+  time_converter_.AddMonotonic(
+      {BootTimestamp::epoch(), BootTimestamp::epoch() + chrono::seconds(1000)});
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(10000));
+  }
+
+  // Confirm that we can parse the result.  LogReader has enough internal CHECKs
+  // to confirm the right thing happened.
+  ConfirmReadable(MakePi1DeadNodeLogfiles());
+}
+
+// Tests that we can relog with a different config.  This makes most sense when
+// you are trying to edit a log and want to use channel renaming + the original
+// config in the new log.
+TEST_P(MultinodeLoggerTest, LogDifferentConfig) {
+  time_converter_.StartEqual();
+  {
+    LoggerState pi1_logger = MakeLogger(pi1_);
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(95));
+
+    StartLogger(&pi1_logger);
+    StartLogger(&pi2_logger);
+
+    event_loop_factory_.RunFor(chrono::milliseconds(20000));
+  }
+
+  LogReader reader(SortParts(logfiles_));
+  reader.RemapLoggedChannel<aos::examples::Ping>("/test", "/original");
+
+  SimulatedEventLoopFactory log_reader_factory(reader.configuration());
+  log_reader_factory.set_send_delay(chrono::microseconds(0));
+
+  // This sends out the fetched messages and advances time to the start of the
+  // log file.
+  reader.Register(&log_reader_factory);
+
+  const Node *pi1 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi1");
+  const Node *pi2 =
+      configuration::GetNode(log_reader_factory.configuration(), "pi2");
+
+  LOG(INFO) << "Start time " << reader.monotonic_start_time(pi1) << " pi1";
+  LOG(INFO) << "Start time " << reader.monotonic_start_time(pi2) << " pi2";
+  LOG(INFO) << "now pi1 "
+            << log_reader_factory.GetNodeEventLoopFactory(pi1)->monotonic_now();
+  LOG(INFO) << "now pi2 "
+            << log_reader_factory.GetNodeEventLoopFactory(pi2)->monotonic_now();
+
+  EXPECT_THAT(reader.LoggedNodes(),
+              ::testing::ElementsAre(
+                  configuration::GetNode(reader.logged_configuration(), pi1),
+                  configuration::GetNode(reader.logged_configuration(), pi2)));
+
+  reader.event_loop_factory()->set_send_delay(chrono::microseconds(0));
+
+  // And confirm we can re-create a log again, while checking the contents.
+  std::vector<std::string> log_files;
+  {
+    LoggerState pi1_logger =
+        MakeLogger(log_reader_factory.GetNodeEventLoopFactory("pi1"),
+                   &log_reader_factory, reader.logged_configuration());
+    LoggerState pi2_logger =
+        MakeLogger(log_reader_factory.GetNodeEventLoopFactory("pi2"),
+                   &log_reader_factory, reader.logged_configuration());
+
+    pi1_logger.StartLogger(tmp_dir_ + "/relogged1");
+    pi2_logger.StartLogger(tmp_dir_ + "/relogged2");
+
+    log_reader_factory.Run();
+
+    for (auto &x : pi1_logger.log_namer->all_filenames()) {
+      log_files.emplace_back(absl::StrCat(tmp_dir_, "/relogged1_", x));
+    }
+    for (auto &x : pi2_logger.log_namer->all_filenames()) {
+      log_files.emplace_back(absl::StrCat(tmp_dir_, "/relogged2_", x));
+    }
+  }
+
+  reader.Deregister();
+
+  // And verify that we can run the LogReader over the relogged files without
+  // hitting any fatal errors.
+  {
+    LogReader relogged_reader(SortParts(log_files));
+    relogged_reader.Register();
+
+    relogged_reader.event_loop_factory()->Run();
+  }
+}
+
+// Tests that we properly replay a log where the start time for a node is before
+// any data on the node.  This can happen if the logger starts before data is
+// published.  While the scenario below is a bit convoluted, we have seen logs
+// like this generated out in the wild.
+TEST(MultinodeRebootLoggerTest, StartTimeBeforeData) {
+  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
+      aos::configuration::ReadConfig(ArtifactPath(
+          "aos/events/logging/multinode_pingpong_split3_config.json"));
+  message_bridge::TestingTimeConverter time_converter(
+      configuration::NodesCount(&config.message()));
+  SimulatedEventLoopFactory event_loop_factory(&config.message());
+  event_loop_factory.SetTimeConverter(&time_converter);
+  NodeEventLoopFactory *const pi1 =
+      event_loop_factory.GetNodeEventLoopFactory("pi1");
+  const size_t pi1_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi1->node());
+  NodeEventLoopFactory *const pi2 =
+      event_loop_factory.GetNodeEventLoopFactory("pi2");
+  const size_t pi2_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi2->node());
+  NodeEventLoopFactory *const pi3 =
+      event_loop_factory.GetNodeEventLoopFactory("pi3");
+  const size_t pi3_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi3->node());
+
+  const std::string kLogfile1_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile1/";
+  const std::string kLogfile2_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile2.1/";
+  const std::string kLogfile2_2 =
+      aos::testing::TestTmpDir() + "/multi_logfile2.2/";
+  const std::string kLogfile3_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile3/";
+  util::UnlinkRecursive(kLogfile1_1);
+  util::UnlinkRecursive(kLogfile2_1);
+  util::UnlinkRecursive(kLogfile2_2);
+  util::UnlinkRecursive(kLogfile3_1);
+  const UUID pi1_boot0 = UUID::Random();
+  const UUID pi2_boot0 = UUID::Random();
+  const UUID pi2_boot1 = UUID::Random();
+  const UUID pi3_boot0 = UUID::Random();
+  {
+    CHECK_EQ(pi1_index, 0u);
+    CHECK_EQ(pi2_index, 1u);
+    CHECK_EQ(pi3_index, 2u);
+
+    time_converter.set_boot_uuid(pi1_index, 0, pi1_boot0);
+    time_converter.set_boot_uuid(pi2_index, 0, pi2_boot0);
+    time_converter.set_boot_uuid(pi2_index, 1, pi2_boot1);
+    time_converter.set_boot_uuid(pi3_index, 0, pi3_boot0);
+
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch(),
+        {BootTimestamp::epoch(), BootTimestamp::epoch(),
+         BootTimestamp::epoch()});
+    const chrono::nanoseconds reboot_time = chrono::milliseconds(20000);
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch() + reboot_time,
+        {BootTimestamp::epoch() + reboot_time,
+         BootTimestamp{
+             .boot = 1,
+             .time = monotonic_clock::epoch() + chrono::milliseconds(1323)},
+         BootTimestamp::epoch() + reboot_time});
+  }
+
+  // Make everything perfectly quiet.
+  event_loop_factory.SkipTimingReport();
+  event_loop_factory.DisableStatistics();
+
+  std::vector<std::string> filenames;
+  {
+    LoggerState pi1_logger = MakeLoggerState(
+        pi1, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+    LoggerState pi3_logger = MakeLoggerState(
+        pi3, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+    {
+      // And now start the logger.
+      LoggerState pi2_logger = MakeLoggerState(
+          pi2, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+
+      event_loop_factory.RunFor(chrono::milliseconds(1000));
+
+      pi1_logger.StartLogger(kLogfile1_1);
+      pi3_logger.StartLogger(kLogfile3_1);
+      pi2_logger.StartLogger(kLogfile2_1);
+
+      event_loop_factory.RunFor(chrono::milliseconds(10000));
+
+      // Now that we've got a start time in the past, turn on data.
+      event_loop_factory.EnableStatistics();
+      std::unique_ptr<aos::EventLoop> ping_event_loop =
+          pi1->MakeEventLoop("ping");
+      Ping ping(ping_event_loop.get());
+
+      pi2->AlwaysStart<Pong>("pong");
+
+      event_loop_factory.RunFor(chrono::milliseconds(3000));
+
+      pi2_logger.AppendAllFilenames(&filenames);
+
+      // Stop logging on pi2 before rebooting and completely shut off all
+      // messages on pi2.
+      pi2->DisableStatistics();
+      pi1->Disconnect(pi2->node());
+      pi2->Disconnect(pi1->node());
+    }
+    event_loop_factory.RunFor(chrono::milliseconds(7000));
+    // pi2 now reboots.
+    {
+      event_loop_factory.RunFor(chrono::milliseconds(1000));
+
+      // Start logging again on pi2 after it is up.
+      LoggerState pi2_logger = MakeLoggerState(
+          pi2, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+      pi2_logger.StartLogger(kLogfile2_2);
+
+      event_loop_factory.RunFor(chrono::milliseconds(10000));
+      // And, now that we have a start time in the log, turn data back on.
+      pi2->EnableStatistics();
+      pi1->Connect(pi2->node());
+      pi2->Connect(pi1->node());
+
+      pi2->AlwaysStart<Pong>("pong");
+      std::unique_ptr<aos::EventLoop> ping_event_loop =
+          pi1->MakeEventLoop("ping");
+      Ping ping(ping_event_loop.get());
+
+      event_loop_factory.RunFor(chrono::milliseconds(3000));
+
+      pi2_logger.AppendAllFilenames(&filenames);
+    }
+
+    pi1_logger.AppendAllFilenames(&filenames);
+    pi3_logger.AppendAllFilenames(&filenames);
+  }
+
+  // Confirm that we can parse the result.  LogReader has enough internal CHECKs
+  // to confirm the right thing happened.
+  const std::vector<LogFile> sorted_parts = SortParts(filenames);
+  auto result = ConfirmReadable(filenames);
+  EXPECT_THAT(result[0].first, ::testing::ElementsAre(realtime_clock::epoch() +
+                                                      chrono::seconds(1)));
+  EXPECT_THAT(result[0].second,
+              ::testing::ElementsAre(realtime_clock::epoch() +
+                                     chrono::microseconds(34990350)));
+
+  EXPECT_THAT(result[1].first,
+              ::testing::ElementsAre(
+                  realtime_clock::epoch() + chrono::seconds(1),
+                  realtime_clock::epoch() + chrono::microseconds(3323000)));
+  EXPECT_THAT(result[1].second,
+              ::testing::ElementsAre(
+                  realtime_clock::epoch() + chrono::microseconds(13990200),
+                  realtime_clock::epoch() + chrono::microseconds(16313200)));
+
+  EXPECT_THAT(result[2].first, ::testing::ElementsAre(realtime_clock::epoch() +
+                                                      chrono::seconds(1)));
+  EXPECT_THAT(result[2].second,
+              ::testing::ElementsAre(realtime_clock::epoch() +
+                                     chrono::microseconds(34900150)));
+}
+
+// Tests that local data before remote data after reboot is properly replayed.
+// We only trigger a reboot in the timestamp interpolation function when solving
+// the timestamp problem when we actually have a point in the function.  This
+// originally only happened when a point passes the noncausal filter.  At the
+// start of time for the second boot, if we aren't careful, we will have
+// messages which need to be published at times before the boot.  This happens
+// when a local message is in the log before a forwarded message, so there is no
+// point in the interpolation function.  This delays the reboot.  So, we need to
+// recreate that situation and make sure it doesn't come back.
+TEST(MultinodeRebootLoggerTest,
+     LocalMessageBeforeRemoteBeforeStartAfterReboot) {
+  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
+      aos::configuration::ReadConfig(ArtifactPath(
+          "aos/events/logging/multinode_pingpong_split3_config.json"));
+  message_bridge::TestingTimeConverter time_converter(
+      configuration::NodesCount(&config.message()));
+  SimulatedEventLoopFactory event_loop_factory(&config.message());
+  event_loop_factory.SetTimeConverter(&time_converter);
+  NodeEventLoopFactory *const pi1 =
+      event_loop_factory.GetNodeEventLoopFactory("pi1");
+  const size_t pi1_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi1->node());
+  NodeEventLoopFactory *const pi2 =
+      event_loop_factory.GetNodeEventLoopFactory("pi2");
+  const size_t pi2_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi2->node());
+  NodeEventLoopFactory *const pi3 =
+      event_loop_factory.GetNodeEventLoopFactory("pi3");
+  const size_t pi3_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi3->node());
+
+  const std::string kLogfile1_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile1/";
+  const std::string kLogfile2_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile2.1/";
+  const std::string kLogfile2_2 =
+      aos::testing::TestTmpDir() + "/multi_logfile2.2/";
+  const std::string kLogfile3_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile3/";
+  util::UnlinkRecursive(kLogfile1_1);
+  util::UnlinkRecursive(kLogfile2_1);
+  util::UnlinkRecursive(kLogfile2_2);
+  util::UnlinkRecursive(kLogfile3_1);
+  const UUID pi1_boot0 = UUID::Random();
+  const UUID pi2_boot0 = UUID::Random();
+  const UUID pi2_boot1 = UUID::Random();
+  const UUID pi3_boot0 = UUID::Random();
+  {
+    CHECK_EQ(pi1_index, 0u);
+    CHECK_EQ(pi2_index, 1u);
+    CHECK_EQ(pi3_index, 2u);
+
+    time_converter.set_boot_uuid(pi1_index, 0, pi1_boot0);
+    time_converter.set_boot_uuid(pi2_index, 0, pi2_boot0);
+    time_converter.set_boot_uuid(pi2_index, 1, pi2_boot1);
+    time_converter.set_boot_uuid(pi3_index, 0, pi3_boot0);
+
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch(),
+        {BootTimestamp::epoch(), BootTimestamp::epoch(),
+         BootTimestamp::epoch()});
+    const chrono::nanoseconds reboot_time = chrono::milliseconds(5000);
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch() + reboot_time,
+        {BootTimestamp::epoch() + reboot_time,
+         BootTimestamp{.boot = 1,
+                       .time = monotonic_clock::epoch() + reboot_time +
+                               chrono::seconds(100)},
+         BootTimestamp::epoch() + reboot_time});
+  }
+
+  std::vector<std::string> filenames;
+  {
+    LoggerState pi1_logger = MakeLoggerState(
+        pi1, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+    LoggerState pi3_logger = MakeLoggerState(
+        pi3, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+    {
+      // And now start the logger.
+      LoggerState pi2_logger = MakeLoggerState(
+          pi2, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+
+      pi1_logger.StartLogger(kLogfile1_1);
+      pi3_logger.StartLogger(kLogfile3_1);
+      pi2_logger.StartLogger(kLogfile2_1);
+
+      event_loop_factory.RunFor(chrono::milliseconds(1005));
+
+      // Now that we've got a start time in the past, turn on data.
+      std::unique_ptr<aos::EventLoop> ping_event_loop =
+          pi1->MakeEventLoop("ping");
+      Ping ping(ping_event_loop.get());
+
+      pi2->AlwaysStart<Pong>("pong");
+
+      event_loop_factory.RunFor(chrono::milliseconds(3000));
+
+      pi2_logger.AppendAllFilenames(&filenames);
+
+      // Disable any remote messages on pi2.
+      pi1->Disconnect(pi2->node());
+      pi2->Disconnect(pi1->node());
+    }
+    event_loop_factory.RunFor(chrono::milliseconds(995));
+    // pi2 now reboots at 5 seconds.
+    {
+      event_loop_factory.RunFor(chrono::milliseconds(1000));
+
+      // Make local stuff happen before we start logging and connect the remote.
+      pi2->AlwaysStart<Pong>("pong");
+      std::unique_ptr<aos::EventLoop> ping_event_loop =
+          pi1->MakeEventLoop("ping");
+      Ping ping(ping_event_loop.get());
+      event_loop_factory.RunFor(chrono::milliseconds(1005));
+
+      // Start logging again on pi2 after it is up.
+      LoggerState pi2_logger = MakeLoggerState(
+          pi2, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+      pi2_logger.StartLogger(kLogfile2_2);
+
+      // And allow remote messages now that we have some local ones.
+      pi1->Connect(pi2->node());
+      pi2->Connect(pi1->node());
+
+      event_loop_factory.RunFor(chrono::milliseconds(1000));
+
+      event_loop_factory.RunFor(chrono::milliseconds(3000));
+
+      pi2_logger.AppendAllFilenames(&filenames);
+    }
+
+    pi1_logger.AppendAllFilenames(&filenames);
+    pi3_logger.AppendAllFilenames(&filenames);
+  }
+
+  // Confirm that we can parse the result.  LogReader has enough internal CHECKs
+  // to confirm the right thing happened.
+  const std::vector<LogFile> sorted_parts = SortParts(filenames);
+  auto result = ConfirmReadable(filenames);
+
+  EXPECT_THAT(result[0].first, ::testing::ElementsAre(realtime_clock::epoch()));
+  EXPECT_THAT(result[0].second,
+              ::testing::ElementsAre(realtime_clock::epoch() +
+                                     chrono::microseconds(11000350)));
+
+  EXPECT_THAT(result[1].first,
+              ::testing::ElementsAre(
+                  realtime_clock::epoch(),
+                  realtime_clock::epoch() + chrono::microseconds(107005000)));
+  EXPECT_THAT(result[1].second,
+              ::testing::ElementsAre(
+                  realtime_clock::epoch() + chrono::microseconds(4000150),
+                  realtime_clock::epoch() + chrono::microseconds(111000200)));
+
+  EXPECT_THAT(result[2].first, ::testing::ElementsAre(realtime_clock::epoch()));
+  EXPECT_THAT(result[2].second,
+              ::testing::ElementsAre(realtime_clock::epoch() +
+                                     chrono::microseconds(11000150)));
+
+  auto start_stop_result = ConfirmReadable(
+      filenames, realtime_clock::epoch() + chrono::milliseconds(2000),
+      realtime_clock::epoch() + chrono::milliseconds(3000));
+
+  EXPECT_THAT(
+      start_stop_result[0].first,
+      ::testing::ElementsAre(realtime_clock::epoch() + chrono::seconds(2)));
+  EXPECT_THAT(
+      start_stop_result[0].second,
+      ::testing::ElementsAre(realtime_clock::epoch() + chrono::seconds(3)));
+  EXPECT_THAT(
+      start_stop_result[1].first,
+      ::testing::ElementsAre(realtime_clock::epoch() + chrono::seconds(2)));
+  EXPECT_THAT(
+      start_stop_result[1].second,
+      ::testing::ElementsAre(realtime_clock::epoch() + chrono::seconds(3)));
+  EXPECT_THAT(
+      start_stop_result[2].first,
+      ::testing::ElementsAre(realtime_clock::epoch() + chrono::seconds(2)));
+  EXPECT_THAT(
+      start_stop_result[2].second,
+      ::testing::ElementsAre(realtime_clock::epoch() + chrono::seconds(3)));
+}
+
+// Tests that setting the start and stop flags across a reboot works as
+// expected.
+TEST(MultinodeRebootLoggerTest, RebootStartStopTimes) {
+  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
+      aos::configuration::ReadConfig(ArtifactPath(
+          "aos/events/logging/multinode_pingpong_split3_config.json"));
+  message_bridge::TestingTimeConverter time_converter(
+      configuration::NodesCount(&config.message()));
+  SimulatedEventLoopFactory event_loop_factory(&config.message());
+  event_loop_factory.SetTimeConverter(&time_converter);
+  NodeEventLoopFactory *const pi1 =
+      event_loop_factory.GetNodeEventLoopFactory("pi1");
+  const size_t pi1_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi1->node());
+  NodeEventLoopFactory *const pi2 =
+      event_loop_factory.GetNodeEventLoopFactory("pi2");
+  const size_t pi2_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi2->node());
+  NodeEventLoopFactory *const pi3 =
+      event_loop_factory.GetNodeEventLoopFactory("pi3");
+  const size_t pi3_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi3->node());
+
+  const std::string kLogfile1_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile1/";
+  const std::string kLogfile2_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile2.1/";
+  const std::string kLogfile2_2 =
+      aos::testing::TestTmpDir() + "/multi_logfile2.2/";
+  const std::string kLogfile3_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile3/";
+  util::UnlinkRecursive(kLogfile1_1);
+  util::UnlinkRecursive(kLogfile2_1);
+  util::UnlinkRecursive(kLogfile2_2);
+  util::UnlinkRecursive(kLogfile3_1);
+  {
+    CHECK_EQ(pi1_index, 0u);
+    CHECK_EQ(pi2_index, 1u);
+    CHECK_EQ(pi3_index, 2u);
+
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch(),
+        {BootTimestamp::epoch(), BootTimestamp::epoch(),
+         BootTimestamp::epoch()});
+    const chrono::nanoseconds reboot_time = chrono::milliseconds(5000);
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch() + reboot_time,
+        {BootTimestamp::epoch() + reboot_time,
+         BootTimestamp{.boot = 1,
+                       .time = monotonic_clock::epoch() + reboot_time},
+         BootTimestamp::epoch() + reboot_time});
+  }
+
+  std::vector<std::string> filenames;
+  {
+    LoggerState pi1_logger = MakeLoggerState(
+        pi1, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+    LoggerState pi3_logger = MakeLoggerState(
+        pi3, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+    {
+      // And now start the logger.
+      LoggerState pi2_logger = MakeLoggerState(
+          pi2, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+
+      pi1_logger.StartLogger(kLogfile1_1);
+      pi3_logger.StartLogger(kLogfile3_1);
+      pi2_logger.StartLogger(kLogfile2_1);
+
+      event_loop_factory.RunFor(chrono::milliseconds(1005));
+
+      // Now that we've got a start time in the past, turn on data.
+      std::unique_ptr<aos::EventLoop> ping_event_loop =
+          pi1->MakeEventLoop("ping");
+      Ping ping(ping_event_loop.get());
+
+      pi2->AlwaysStart<Pong>("pong");
+
+      event_loop_factory.RunFor(chrono::milliseconds(3000));
+
+      pi2_logger.AppendAllFilenames(&filenames);
+    }
+    event_loop_factory.RunFor(chrono::milliseconds(995));
+    // pi2 now reboots at 5 seconds.
+    {
+      event_loop_factory.RunFor(chrono::milliseconds(1000));
+
+      // Make local stuff happen before we start logging and connect the remote.
+      pi2->AlwaysStart<Pong>("pong");
+      std::unique_ptr<aos::EventLoop> ping_event_loop =
+          pi1->MakeEventLoop("ping");
+      Ping ping(ping_event_loop.get());
+      event_loop_factory.RunFor(chrono::milliseconds(5));
+
+      // Start logging again on pi2 after it is up.
+      LoggerState pi2_logger = MakeLoggerState(
+          pi2, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+      pi2_logger.StartLogger(kLogfile2_2);
+
+      event_loop_factory.RunFor(chrono::milliseconds(5000));
+
+      pi2_logger.AppendAllFilenames(&filenames);
+    }
+
+    pi1_logger.AppendAllFilenames(&filenames);
+    pi3_logger.AppendAllFilenames(&filenames);
+  }
+
+  const std::vector<LogFile> sorted_parts = SortParts(filenames);
+  auto result = ConfirmReadable(filenames);
+
+  EXPECT_THAT(result[0].first, ::testing::ElementsAre(realtime_clock::epoch()));
+  EXPECT_THAT(result[0].second,
+              ::testing::ElementsAre(realtime_clock::epoch() +
+                                     chrono::microseconds(11000350)));
+
+  EXPECT_THAT(result[1].first,
+              ::testing::ElementsAre(
+                  realtime_clock::epoch(),
+                  realtime_clock::epoch() + chrono::microseconds(6005000)));
+  EXPECT_THAT(result[1].second,
+              ::testing::ElementsAre(
+                  realtime_clock::epoch() + chrono::microseconds(4900150),
+                  realtime_clock::epoch() + chrono::microseconds(11000200)));
+
+  EXPECT_THAT(result[2].first, ::testing::ElementsAre(realtime_clock::epoch()));
+  EXPECT_THAT(result[2].second,
+              ::testing::ElementsAre(realtime_clock::epoch() +
+                                     chrono::microseconds(11000150)));
+
+  // Confirm we observed the correct start and stop times.  We should see the
+  // reboot here.
+  auto start_stop_result = ConfirmReadable(
+      filenames, realtime_clock::epoch() + chrono::milliseconds(2000),
+      realtime_clock::epoch() + chrono::milliseconds(8000));
+
+  EXPECT_THAT(
+      start_stop_result[0].first,
+      ::testing::ElementsAre(realtime_clock::epoch() + chrono::seconds(2)));
+  EXPECT_THAT(
+      start_stop_result[0].second,
+      ::testing::ElementsAre(realtime_clock::epoch() + chrono::seconds(8)));
+  EXPECT_THAT(start_stop_result[1].first,
+              ::testing::ElementsAre(
+                  realtime_clock::epoch() + chrono::seconds(2),
+                  realtime_clock::epoch() + chrono::microseconds(6005000)));
+  EXPECT_THAT(start_stop_result[1].second,
+              ::testing::ElementsAre(
+                  realtime_clock::epoch() + chrono::microseconds(4900150),
+                  realtime_clock::epoch() + chrono::seconds(8)));
+  EXPECT_THAT(
+      start_stop_result[2].first,
+      ::testing::ElementsAre(realtime_clock::epoch() + chrono::seconds(2)));
+  EXPECT_THAT(
+      start_stop_result[2].second,
+      ::testing::ElementsAre(realtime_clock::epoch() + chrono::seconds(8)));
+}
+
+// Tests that we properly handle one direction being down.
+TEST(MissingDirectionTest, OneDirection) {
+  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
+      aos::configuration::ReadConfig(ArtifactPath(
+          "aos/events/logging/multinode_pingpong_split4_config.json"));
+  message_bridge::TestingTimeConverter time_converter(
+      configuration::NodesCount(&config.message()));
+  SimulatedEventLoopFactory event_loop_factory(&config.message());
+  event_loop_factory.SetTimeConverter(&time_converter);
+
+  NodeEventLoopFactory *const pi1 =
+      event_loop_factory.GetNodeEventLoopFactory("pi1");
+  const size_t pi1_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi1->node());
+  NodeEventLoopFactory *const pi2 =
+      event_loop_factory.GetNodeEventLoopFactory("pi2");
+  const size_t pi2_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi2->node());
+  std::vector<std::string> filenames;
+
+  {
+    CHECK_EQ(pi1_index, 0u);
+    CHECK_EQ(pi2_index, 1u);
+
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch(),
+        {BootTimestamp::epoch(), BootTimestamp::epoch()});
+
+    const chrono::nanoseconds reboot_time = chrono::milliseconds(5000);
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch() + reboot_time,
+        {BootTimestamp{.boot = 1, .time = monotonic_clock::epoch()},
+         BootTimestamp::epoch() + reboot_time});
+  }
+
+  const std::string kLogfile2_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile2.1/";
+  const std::string kLogfile1_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile1.1/";
+  util::UnlinkRecursive(kLogfile2_1);
+  util::UnlinkRecursive(kLogfile1_1);
+
+  pi2->Disconnect(pi1->node());
+
+  pi1->AlwaysStart<Ping>("ping");
+  pi2->AlwaysStart<Pong>("pong");
+
+  {
+    LoggerState pi2_logger = MakeLoggerState(
+        pi2, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+
+    event_loop_factory.RunFor(chrono::milliseconds(95));
+
+    pi2_logger.StartLogger(kLogfile2_1);
+
+    event_loop_factory.RunFor(chrono::milliseconds(6000));
+
+    pi2->Connect(pi1->node());
+
+    LoggerState pi1_logger = MakeLoggerState(
+        pi1, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+    pi1_logger.StartLogger(kLogfile1_1);
+
+    event_loop_factory.RunFor(chrono::milliseconds(5000));
+    pi1_logger.AppendAllFilenames(&filenames);
+    pi2_logger.AppendAllFilenames(&filenames);
+  }
+
+  const std::vector<LogFile> sorted_parts = SortParts(filenames);
+  ConfirmReadable(filenames);
+}
+
+// Tests that we properly handle only one direction ever existing after a
+// reboot.
+TEST(MissingDirectionTest, OneDirectionAfterReboot) {
+  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
+      aos::configuration::ReadConfig(ArtifactPath(
+          "aos/events/logging/multinode_pingpong_split4_config.json"));
+  message_bridge::TestingTimeConverter time_converter(
+      configuration::NodesCount(&config.message()));
+  SimulatedEventLoopFactory event_loop_factory(&config.message());
+  event_loop_factory.SetTimeConverter(&time_converter);
+
+  NodeEventLoopFactory *const pi1 =
+      event_loop_factory.GetNodeEventLoopFactory("pi1");
+  const size_t pi1_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi1->node());
+  NodeEventLoopFactory *const pi2 =
+      event_loop_factory.GetNodeEventLoopFactory("pi2");
+  const size_t pi2_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi2->node());
+  std::vector<std::string> filenames;
+
+  {
+    CHECK_EQ(pi1_index, 0u);
+    CHECK_EQ(pi2_index, 1u);
+
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch(),
+        {BootTimestamp::epoch(), BootTimestamp::epoch()});
+
+    const chrono::nanoseconds reboot_time = chrono::milliseconds(5000);
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch() + reboot_time,
+        {BootTimestamp{.boot = 1, .time = monotonic_clock::epoch()},
+         BootTimestamp::epoch() + reboot_time});
+  }
+
+  const std::string kLogfile2_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile2.1/";
+  util::UnlinkRecursive(kLogfile2_1);
+
+  pi1->AlwaysStart<Ping>("ping");
+
+  // Pi1 sends to pi2.  Reboot pi1, but don't let pi2 connect to pi1.  This
+  // makes it such that we will only get timestamps from pi1 -> pi2 on the
+  // second boot.
+  {
+    LoggerState pi2_logger = MakeLoggerState(
+        pi2, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+
+    event_loop_factory.RunFor(chrono::milliseconds(95));
+
+    pi2_logger.StartLogger(kLogfile2_1);
+
+    event_loop_factory.RunFor(chrono::milliseconds(4000));
+
+    pi2->Disconnect(pi1->node());
+
+    event_loop_factory.RunFor(chrono::milliseconds(1000));
+    pi1->AlwaysStart<Ping>("ping");
+
+    event_loop_factory.RunFor(chrono::milliseconds(5000));
+    pi2_logger.AppendAllFilenames(&filenames);
+  }
+
+  const std::vector<LogFile> sorted_parts = SortParts(filenames);
+  ConfirmReadable(filenames);
+}
+
+// Tests that we properly handle only one direction ever existing after a reboot
+// with only reliable data.
+TEST(MissingDirectionTest, OneDirectionAfterRebootReliable) {
+  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
+      aos::configuration::ReadConfig(ArtifactPath(
+          "aos/events/logging/multinode_pingpong_split4_reliable_config.json"));
+  message_bridge::TestingTimeConverter time_converter(
+      configuration::NodesCount(&config.message()));
+  SimulatedEventLoopFactory event_loop_factory(&config.message());
+  event_loop_factory.SetTimeConverter(&time_converter);
+
+  NodeEventLoopFactory *const pi1 =
+      event_loop_factory.GetNodeEventLoopFactory("pi1");
+  const size_t pi1_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi1->node());
+  NodeEventLoopFactory *const pi2 =
+      event_loop_factory.GetNodeEventLoopFactory("pi2");
+  const size_t pi2_index = configuration::GetNodeIndex(
+      event_loop_factory.configuration(), pi2->node());
+  std::vector<std::string> filenames;
+
+  {
+    CHECK_EQ(pi1_index, 0u);
+    CHECK_EQ(pi2_index, 1u);
+
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch(),
+        {BootTimestamp::epoch(), BootTimestamp::epoch()});
+
+    const chrono::nanoseconds reboot_time = chrono::milliseconds(5000);
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch() + reboot_time,
+        {BootTimestamp{.boot = 1, .time = monotonic_clock::epoch()},
+         BootTimestamp::epoch() + reboot_time});
+  }
+
+  const std::string kLogfile2_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile2.1/";
+  util::UnlinkRecursive(kLogfile2_1);
+
+  pi1->AlwaysStart<Ping>("ping");
+
+  // Pi1 sends to pi2.  Reboot pi1, but don't let pi2 connect to pi1.  This
+  // makes it such that we will only get timestamps from pi1 -> pi2 on the
+  // second boot.
+  {
+    LoggerState pi2_logger = MakeLoggerState(
+        pi2, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+
+    event_loop_factory.RunFor(chrono::milliseconds(95));
+
+    pi2_logger.StartLogger(kLogfile2_1);
+
+    event_loop_factory.RunFor(chrono::milliseconds(4000));
+
+    pi2->Disconnect(pi1->node());
+
+    event_loop_factory.RunFor(chrono::milliseconds(1000));
+    pi1->AlwaysStart<Ping>("ping");
+
+    event_loop_factory.RunFor(chrono::milliseconds(5000));
+    pi2_logger.AppendAllFilenames(&filenames);
+  }
+
+  const std::vector<LogFile> sorted_parts = SortParts(filenames);
+  ConfirmReadable(filenames);
+}
+
+// Tests that we properly handle what used to be a time violation in one
+// direction.  This can occur when one direction goes down after sending some
+// data, but the other keeps working.  The down direction ends up resolving to a
+// straight line in the noncausal filter, where the direction which is still up
+// can cross that line.  Really, time progressed along just fine but we assumed
+// that the offset was a line when it could have deviated by up to 1ms/second.
+TEST_P(MultinodeLoggerTest, OneDirectionTimeDrift) {
+  std::vector<std::string> filenames;
+
+  CHECK_EQ(pi1_index_, 0u);
+  CHECK_EQ(pi2_index_, 1u);
+
+  time_converter_.AddNextTimestamp(
+      distributed_clock::epoch(),
+      {BootTimestamp::epoch(), BootTimestamp::epoch()});
+
+  const chrono::nanoseconds before_disconnect_duration =
+      time_converter_.AddMonotonic(
+          {chrono::milliseconds(1000), chrono::milliseconds(1000)});
+
+  const chrono::nanoseconds test_duration =
+      time_converter_.AddMonotonic(
+          {chrono::milliseconds(1000), chrono::milliseconds(1000)}) +
+      time_converter_.AddMonotonic(
+          {chrono::milliseconds(10000),
+           chrono::milliseconds(10000) - chrono::milliseconds(5)}) +
+      time_converter_.AddMonotonic(
+          {chrono::milliseconds(10000),
+           chrono::milliseconds(10000) + chrono::milliseconds(5)});
+
+  const std::string kLogfile =
+      aos::testing::TestTmpDir() + "/multi_logfile2.1/";
+  util::UnlinkRecursive(kLogfile);
+
+  {
+    LoggerState pi2_logger = MakeLogger(pi2_);
+    pi2_logger.StartLogger(kLogfile);
+    event_loop_factory_.RunFor(before_disconnect_duration);
+
+    pi2_->Disconnect(pi1_->node());
+
+    event_loop_factory_.RunFor(test_duration);
+    pi2_->Connect(pi1_->node());
+
+    event_loop_factory_.RunFor(chrono::milliseconds(5000));
+    pi2_logger.AppendAllFilenames(&filenames);
+  }
+
+  const std::vector<LogFile> sorted_parts = SortParts(filenames);
+  ConfirmReadable(filenames);
+}
+
+// Tests that we can replay a logfile that has timestamps such that at least one
+// node's epoch is at a positive distributed_clock (and thus will have to be
+// booted after the other node(s)).
+TEST_P(MultinodeLoggerTest, StartOneNodeBeforeOther) {
+  std::vector<std::string> filenames;
+
+  CHECK_EQ(pi1_index_, 0u);
+  CHECK_EQ(pi2_index_, 1u);
+
+  time_converter_.AddNextTimestamp(
+      distributed_clock::epoch(),
+      {BootTimestamp::epoch(), BootTimestamp::epoch()});
+
+  const chrono::nanoseconds before_reboot_duration = chrono::milliseconds(1000);
+  time_converter_.RebootAt(
+      0, distributed_clock::time_point(before_reboot_duration));
+
+  const chrono::nanoseconds test_duration = time_converter_.AddMonotonic(
+      {chrono::milliseconds(10000), chrono::milliseconds(10000)});
+
+  const std::string kLogfile =
+      aos::testing::TestTmpDir() + "/multi_logfile2.1/";
+  util::UnlinkRecursive(kLogfile);
+
+  pi2_->Disconnect(pi1_->node());
+  pi1_->Disconnect(pi2_->node());
+
+  {
+    LoggerState pi2_logger = MakeLogger(pi2_);
+
+    pi2_logger.StartLogger(kLogfile);
+    event_loop_factory_.RunFor(before_reboot_duration);
+
+    pi2_->Connect(pi1_->node());
+    pi1_->Connect(pi2_->node());
+
+    event_loop_factory_.RunFor(test_duration);
+
+    pi2_logger.AppendAllFilenames(&filenames);
+  }
+
+  const std::vector<LogFile> sorted_parts = SortParts(filenames);
+  ConfirmReadable(filenames);
+
+  {
+    LogReader reader(sorted_parts);
+    SimulatedEventLoopFactory replay_factory(reader.configuration());
+    reader.RegisterWithoutStarting(&replay_factory);
+
+    NodeEventLoopFactory *const replay_node =
+        reader.event_loop_factory()->GetNodeEventLoopFactory("pi1");
+
+    std::unique_ptr<EventLoop> test_event_loop =
+        replay_node->MakeEventLoop("test_reader");
+    replay_node->OnStartup([replay_node]() {
+      // Check that we didn't boot until at least t=0.
+      CHECK_LE(monotonic_clock::epoch(), replay_node->monotonic_now());
+    });
+    test_event_loop->OnRun([&test_event_loop]() {
+      // Check that we didn't boot until at least t=0.
+      EXPECT_LE(monotonic_clock::epoch(), test_event_loop->monotonic_now());
+    });
+    reader.event_loop_factory()->Run();
+    reader.Deregister();
+  }
+}
+
+// Tests that when we have a loop without all the logs at all points in time, we
+// can sort it properly.
+TEST(MultinodeLoggerLoopTest, Loop) {
+  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
+      aos::configuration::ReadConfig(ArtifactPath(
+          "aos/events/logging/multinode_pingpong_triangle_split_config.json"));
+  message_bridge::TestingTimeConverter time_converter(
+      configuration::NodesCount(&config.message()));
+  SimulatedEventLoopFactory event_loop_factory(&config.message());
+  event_loop_factory.SetTimeConverter(&time_converter);
+
+  NodeEventLoopFactory *const pi1 =
+      event_loop_factory.GetNodeEventLoopFactory("pi1");
+  NodeEventLoopFactory *const pi2 =
+      event_loop_factory.GetNodeEventLoopFactory("pi2");
+  NodeEventLoopFactory *const pi3 =
+      event_loop_factory.GetNodeEventLoopFactory("pi3");
+
+  const std::string kLogfile1_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile1/";
+  const std::string kLogfile2_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile2/";
+  const std::string kLogfile3_1 =
+      aos::testing::TestTmpDir() + "/multi_logfile3/";
+  util::UnlinkRecursive(kLogfile1_1);
+  util::UnlinkRecursive(kLogfile2_1);
+  util::UnlinkRecursive(kLogfile3_1);
+
+  {
+    // Make pi1 boot before everything else.
+    time_converter.AddNextTimestamp(
+        distributed_clock::epoch(),
+        {BootTimestamp::epoch(),
+         BootTimestamp::epoch() - chrono::milliseconds(100),
+         BootTimestamp::epoch() - chrono::milliseconds(300)});
+  }
+
+  // We want to setup a situation such that 2 of the 3 legs of the loop are very
+  // confident about time being X, and the third leg is pulling the average off
+  // to one side.
+  //
+  // It's easiest to visualize this in timestamp_plotter.
+
+  std::vector<std::string> filenames;
+  {
+    // Have pi1 send out a reliable message at startup.  This sets up a long
+    // forwarding time message at the start to bias time.
+    std::unique_ptr<EventLoop> pi1_event_loop = pi1->MakeEventLoop("ping");
+    {
+      aos::Sender<examples::Ping> ping_sender =
+          pi1_event_loop->MakeSender<examples::Ping>("/reliable");
+
+      aos::Sender<examples::Ping>::Builder builder = ping_sender.MakeBuilder();
+      examples::Ping::Builder ping_builder =
+          builder.MakeBuilder<examples::Ping>();
+      CHECK_EQ(builder.Send(ping_builder.Finish()), RawSender::Error::kOk);
+    }
+
+    // Wait a while so there's enough data to let the worst case be rather off.
+    event_loop_factory.RunFor(chrono::seconds(1000));
+
+    // Now start a receiving node first.  This sets up 2 tight bounds between 2
+    // of the nodes.
+    LoggerState pi2_logger = MakeLoggerState(
+        pi2, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+    pi2_logger.StartLogger(kLogfile2_1);
+
+    event_loop_factory.RunFor(chrono::seconds(100));
+
+    // And now start the third leg.
+    LoggerState pi3_logger = MakeLoggerState(
+        pi3, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+    pi3_logger.StartLogger(kLogfile3_1);
+
+    LoggerState pi1_logger = MakeLoggerState(
+        pi1, &event_loop_factory, SupportedCompressionAlgorithms()[0]);
+    pi1_logger.StartLogger(kLogfile1_1);
+
+    event_loop_factory.RunFor(chrono::seconds(100));
+
+    pi1_logger.AppendAllFilenames(&filenames);
+    pi2_logger.AppendAllFilenames(&filenames);
+    pi3_logger.AppendAllFilenames(&filenames);
+  }
+
+  // Make sure we can read this.
+  const std::vector<LogFile> sorted_parts = SortParts(filenames);
+  auto result = ConfirmReadable(filenames);
+}
+
+}  // namespace testing
+}  // namespace logger
+}  // namespace aos