1 files changed, 26 insertions, 7 deletions

diff --git a/googletest/src/gtest.cc b/googletest/src/gtest.cc
index e52dda65..707e1a51 100644
--- a/googletest/src/gtest.cc
+++ b/googletest/src/gtest.cc
@@ -1031,7 +1031,25 @@ std::string UnitTestImpl::CurrentOsStackTraceExceptTop(int skip_count) {
       );  // NOLINT
 }
 
-// Returns the current time in milliseconds.
+// A helper class for measuring elapsed times.
+class Timer {
+ public:
+  Timer() : start_(std::chrono::steady_clock::now()) {}
+
+  // Return time elapsed in milliseconds since the timer was created.
+  TimeInMillis Elapsed() {
+    return std::chrono::duration_cast<std::chrono::milliseconds>(
+               std::chrono::steady_clock::now() - start_)
+        .count();
+  }
+
+ private:
+  std::chrono::time_point<std::chrono::steady_clock> start_;
+};
+
+// Returns a timestamp as milliseconds since the epoch. Note this time may jump
+// around subject to adjustments by the system, to measure elapsed time use
+// Timer instead.
 TimeInMillis GetTimeInMillis() {
   return std::chrono::duration_cast<std::chrono::milliseconds>(
              std::chrono::system_clock::now() -
@@ -2824,7 +2842,8 @@ void TestInfo::Run() {
   // Notifies the unit test event listeners that a test is about to start.
   repeater->OnTestStart(*this);
 
-  const TimeInMillis start = internal::GetTimeInMillis();
+  result_.set_start_timestamp(internal::GetTimeInMillis());
+  internal::Timer timer;
 
   impl->os_stack_trace_getter()->UponLeavingGTest();
 
@@ -2849,8 +2868,7 @@ void TestInfo::Run() {
         test, &Test::DeleteSelf_, "the test fixture's destructor");
   }
 
-  result_.set_start_timestamp(start);
-  result_.set_elapsed_time(internal::GetTimeInMillis() - start);
+  result_.set_elapsed_time(timer.Elapsed());
 
   // Notifies the unit test event listener that a test has just finished.
   repeater->OnTestEnd(*this);
@@ -2992,6 +3010,7 @@ void TestSuite::Run() {
       this, &TestSuite::RunSetUpTestSuite, "SetUpTestSuite()");
 
   start_timestamp_ = internal::GetTimeInMillis();
+  internal::Timer timer;
   for (int i = 0; i < total_test_count(); i++) {
     GetMutableTestInfo(i)->Run();
     if (GTEST_FLAG(fail_fast) && GetMutableTestInfo(i)->result()->Failed()) {
@@ -3001,7 +3020,7 @@ void TestSuite::Run() {
       break;
     }
   }
-  elapsed_time_ = internal::GetTimeInMillis() - start_timestamp_;
+  elapsed_time_ = timer.Elapsed();
 
   impl->os_stack_trace_getter()->UponLeavingGTest();
   internal::HandleExceptionsInMethodIfSupported(
@@ -5685,7 +5704,7 @@ bool UnitTestImpl::RunAllTests() {
     // assertions executed before RUN_ALL_TESTS().
     ClearNonAdHocTestResult();
 
-    const TimeInMillis start = GetTimeInMillis();
+    Timer timer;
 
     // Shuffles test suites and tests if requested.
     if (has_tests_to_run && GTEST_FLAG(shuffle)) {
@@ -5751,7 +5770,7 @@ bool UnitTestImpl::RunAllTests() {
       repeater->OnEnvironmentsTearDownEnd(*parent_);
     }
 
-    elapsed_time_ = GetTimeInMillis() - start;
+    elapsed_time_ = timer.Elapsed();
 
     // Tells the unit test event listener that the tests have just finished.
     repeater->OnTestIterationEnd(*parent_, i);