diff --git a/src/mock-log_unittest.cc b/src/mock-log_unittest.cc
new file mode 100644
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+++ b/src/mock-log_unittest.cc
@@ -0,0 +1,108 @@
+// Copyright (c) 2022, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: Zhanyong Wan
+
+// Tests the ScopedMockLog class.
+
+#include "mock-log.h"
+
+#include <string>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+namespace {
+
+using GOOGLE_NAMESPACE::GLOG_ERROR;
+using GOOGLE_NAMESPACE::GLOG_INFO;
+using GOOGLE_NAMESPACE::GLOG_WARNING;
+using GOOGLE_NAMESPACE::glog_testing::ScopedMockLog;
+using std::string;
+using testing::_;
+using testing::EndsWith;
+using testing::InSequence;
+using testing::InvokeWithoutArgs;
+
+// Tests that ScopedMockLog intercepts LOG()s when it's alive.
+TEST(ScopedMockLogTest, InterceptsLog) {
+  ScopedMockLog log;
+
+  InSequence s;
+  EXPECT_CALL(log,
+              Log(GLOG_WARNING, EndsWith("mock-log_unittest.cc"), "Fishy."));
+  EXPECT_CALL(log, Log(GLOG_INFO, _, "Working..."))
+      .Times(2);
+  EXPECT_CALL(log, Log(GLOG_ERROR, _, "Bad!!"));
+
+  LOG(WARNING) << "Fishy.";
+  LOG(INFO) << "Working...";
+  LOG(INFO) << "Working...";
+  LOG(ERROR) << "Bad!!";
+}
+
+void LogBranch() {
+  LOG(INFO) << "Logging a branch...";
+}
+
+void LogTree() {
+  LOG(INFO) << "Logging the whole tree...";
+}
+
+void LogForest() {
+  LOG(INFO) << "Logging the entire forest.";
+  LOG(INFO) << "Logging the entire forest..";
+  LOG(INFO) << "Logging the entire forest...";
+}
+
+// The purpose of the following test is to verify that intercepting logging
+// continues to work properly if a LOG statement is executed within the scope
+// of a mocked call.
+TEST(ScopedMockLogTest, LogDuringIntercept) {
+  ScopedMockLog log;
+  InSequence s;
+  EXPECT_CALL(log, Log(GLOG_INFO, __FILE__, "Logging a branch..."))
+      .WillOnce(InvokeWithoutArgs(LogTree));
+  EXPECT_CALL(log, Log(GLOG_INFO, __FILE__, "Logging the whole tree..."))
+      .WillOnce(InvokeWithoutArgs(LogForest));
+  EXPECT_CALL(log, Log(GLOG_INFO, __FILE__, "Logging the entire forest."));
+  EXPECT_CALL(log, Log(GLOG_INFO, __FILE__, "Logging the entire forest.."));
+  EXPECT_CALL(log, Log(GLOG_INFO, __FILE__, "Logging the entire forest..."));
+  LogBranch();
+}
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  GOOGLE_NAMESPACE::InitGoogleLogging(argv[0]);
+  testing::InitGoogleTest(&argc, argv);
+  testing::InitGoogleMock(&argc, argv);
+
+  return RUN_ALL_TESTS();
+}