412 - Make timestamp generator monotonic

Fix test build issue on Windows.

Author: mpenick

test/unit_tests/src/test_get_time.cpp

@@ -20,8 +20,8 @@
 
 #include "get_time.hpp"
 
-#include <unistd.h>
 #include <boost/test/unit_test.hpp>
+#include <boost/thread/thread.hpp>
 
 BOOST_AUTO_TEST_SUITE(get_time)
 
@@ -37,12 +37,21 @@ BOOST_AUTO_TEST_CASE(monotonic)
 
 BOOST_AUTO_TEST_CASE(monotonic_duration)
 {
+  // Sleep can be off by as much as 10+ ms on most systems (or >10% for 100ms)
+  double tolerance = 15.0;
+
+#ifdef _WIN32
+  // Sleep can be off more on Windows; increasing tolerance
+  // https://msdn.microsoft.com/en-us/library/windows/desktop/ms686298(v=vs.85).aspx
+  tolerance = 25.0;
+#endif
+
   uint64_t start = cass::get_time_monotonic_ns();
-  sleep(1);
+  boost::this_thread::sleep_for(boost::chrono::seconds(1));
   uint64_t elapsed = cass::get_time_monotonic_ns() - start;
   BOOST_REQUIRE_CLOSE(static_cast<double>(elapsed),
                       static_cast<double>(NANOSECONDS_PER_SECOND),
-                      1.0); // 1% or +/- 10 milliseconds
+                      tolerance);
 }
 
 BOOST_AUTO_TEST_SUITE_END()

test/unit_tests/src/test_timestamp_gen.cpp

@@ -60,17 +60,16 @@ int run_monotonic_timestamp_gen(uint64_t warning_threshold_us, uint64_t warning_
     elapsed = cass::get_time_since_epoch_ms() - start;
   } while (elapsed < duration_ms);
 
-  double timestamp_rate = (static_cast<double>(timestamp_count) / elapsed) * 1000;
   // We can generate at most 1,000,000 timestamps in a second. If we exceed this
   // limit and the clock skew threshold then a warning log should have been printed.
-  if (timestamp_rate > 1000000.0 &&
-      elapsed * MICROSECONDS_PER_MILLISECOND > warning_threshold_us) {
-    BOOST_CHECK(warn_count > 0);
-  } else {
-    BOOST_TEST_MESSAGE("Warning: The test did not exceed the timestamp generator maximum rate.");
-    BOOST_CHECK(warn_count == 0);
+  double timestamp_rate = (static_cast<double>(timestamp_count) / elapsed) * 1000;
+  if (timestamp_rate <= 1000000.0 ||
+      elapsed * MICROSECONDS_PER_MILLISECOND <= warning_threshold_us) {
+    BOOST_TEST_MESSAGE("Warning: The test may not have exceeded the timestamp generator's maximum rate.");
   }
 
+  BOOST_CHECK(warn_count > 0);
+
   return warn_count;
 }