diff --git a/aos/time/time_test.cc b/aos/time/time_test.cc
index 7b6c1a5..80d273e 100644
--- a/aos/time/time_test.cc
+++ b/aos/time/time_test.cc
@@ -11,44 +11,109 @@
 namespace time {
 namespace testing {
 
-TEST(TimeTest, FromRate) {
-  EXPECT_EQ(::std::chrono::milliseconds(10), FromRate(100));
-}
+namespace chrono = std::chrono;
+
+TEST(TimeTest, FromRate) { EXPECT_EQ(chrono::milliseconds(10), FromRate(100)); }
 
 // Test the monotonic_clock and sleep_until functions.
 TEST(TimeTest, MonotonicClockSleepAndNow) {
   monotonic_clock::time_point start = monotonic_clock::now();
-  const auto kSleepTime = ::std::chrono::milliseconds(500);
+  const auto kSleepTime = chrono::milliseconds(500);
   ::std::this_thread::sleep_until(start + kSleepTime);
   monotonic_clock::time_point end = monotonic_clock::now();
   EXPECT_GE(end - start, kSleepTime);
-  EXPECT_LT(end - start, kSleepTime + ::std::chrono::milliseconds(200));
+  EXPECT_LT(end - start, kSleepTime + chrono::milliseconds(200));
 }
 
 // Test to_timespec for a duration.
 TEST(TimeTest, DurationToTimespec) {
-  struct timespec pos_time = to_timespec(::std::chrono::milliseconds(56262));
+  struct timespec pos_time = to_timespec(chrono::milliseconds(56262));
   EXPECT_EQ(pos_time.tv_sec, 56);
   EXPECT_EQ(pos_time.tv_nsec, 262000000);
 
-  struct timespec neg_time = to_timespec(::std::chrono::milliseconds(-56262));
+  struct timespec neg_time = to_timespec(chrono::milliseconds(-56262));
   EXPECT_EQ(neg_time.tv_sec, -56);
   EXPECT_EQ(neg_time.tv_nsec, -262000000);
 }
 
 // Test to_timespec for a time_point.
 TEST(TimeTest, TimePointToTimespec) {
-  struct timespec pos_time = to_timespec(::aos::monotonic_clock::epoch() +
-                                     ::std::chrono::seconds(1432423));
+  struct timespec pos_time =
+      to_timespec(::aos::monotonic_clock::epoch() + chrono::seconds(1432423));
   EXPECT_EQ(pos_time.tv_sec, 1432423);
   EXPECT_EQ(pos_time.tv_nsec, 0);
 
-  struct timespec neg_time = to_timespec(::aos::monotonic_clock::epoch() -
-                                     ::std::chrono::seconds(1432423));
+  struct timespec neg_time =
+      to_timespec(::aos::monotonic_clock::epoch() - chrono::seconds(1432423));
   EXPECT_EQ(neg_time.tv_sec, -1432423);
   EXPECT_EQ(neg_time.tv_nsec, 0);
 }
 
+// Test that << works with numbers with leading 0's.
+TEST(TimeTest, OperatorStream) {
+  const monotonic_clock::time_point t = monotonic_clock::epoch() +
+                                        chrono::seconds(1432423) +
+                                        chrono::milliseconds(15);
+
+  // And confirm that the stream's settings are restored by adding a random
+  // number afterwords.
+  std::stringstream s;
+  s << t << " and number " << 123;
+
+  EXPECT_EQ(s.str(), "1432423.015000000sec and number 123");
+}
+
+// Test that << works with negative numbers.
+TEST(TimeTest, OperatorStreamNegative) {
+  {
+    const monotonic_clock::time_point t = monotonic_clock::epoch() -
+                                          chrono::seconds(14) +
+                                          chrono::milliseconds(915);
+
+    std::stringstream s;
+    s << t;
+
+    EXPECT_EQ(s.str(), "-13.085000000sec");
+  }
+  {
+    const monotonic_clock::time_point t =
+        monotonic_clock::epoch() - chrono::nanoseconds(1);
+
+    std::stringstream s;
+    s << t;
+
+    EXPECT_EQ(s.str(), "-0.000000001sec");
+  }
+  {
+    const monotonic_clock::time_point t =
+        monotonic_clock::epoch() - chrono::seconds(1) - chrono::nanoseconds(1);
+
+    std::stringstream s;
+    s << t;
+
+    EXPECT_EQ(s.str(), "-1.000000001sec");
+  }
+  {
+    const monotonic_clock::time_point t =
+        monotonic_clock::epoch() - chrono::seconds(2) - chrono::nanoseconds(1);
+
+    std::stringstream s;
+    s << t;
+
+    EXPECT_EQ(s.str(), "-2.000000001sec");
+  }
+}
+
+// Test that << works with min_time.
+TEST(TimeTest, OperatorStreamMinTime) {
+  const monotonic_clock::time_point t = monotonic_clock::min_time;
+
+  std::stringstream s;
+  s << t;
+
+  EXPECT_EQ(s.str(), "-9223372036.854775808sec");
+}
+
 }  // namespace testing
 }  // namespace time
 }  // namespace aos