diff -r 000000000000 -r 6474c204b198 xpcom/tests/TestTimeStamp.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/tests/TestTimeStamp.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,96 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/TimeStamp.h"
+
+#include "TestHarness.h"
+
+#include "prinrval.h"
+#include "prthread.h"
+
+using mozilla::TimeStamp;
+using mozilla::TimeDuration;
+
+static void Assert(bool aCond, const char* aMsg)
+{
+    if (aCond) {
+        passed(aMsg);
+    } else {
+        fail("%s", aMsg);
+    }
+}
+
+int main(int argc, char** argv)
+{
+    ScopedXPCOM xpcom("nsTimeStamp");
+    if (xpcom.failed())
+        return 1;
+
+    TimeDuration td;
+    Assert(td.ToSeconds() == 0.0, "TimeDuration default value 0");
+    Assert(TimeDuration::FromSeconds(5).ToSeconds() == 5.0,
+           "TimeDuration FromSeconds/ToSeconds round-trip");
+    Assert(TimeDuration::FromMilliseconds(5000).ToSeconds() == 5.0,
+           "TimeDuration FromMilliseconds/ToSeconds round-trip");
+    Assert(TimeDuration::FromSeconds(1) < TimeDuration::FromSeconds(2),
+           "TimeDuration < operator works");
+    Assert(!(TimeDuration::FromSeconds(1) < TimeDuration::FromSeconds(1)),
+           "TimeDuration < operator works");
+    Assert(TimeDuration::FromSeconds(2) > TimeDuration::FromSeconds(1),
+           "TimeDuration > operator works");
+    Assert(!(TimeDuration::FromSeconds(1) > TimeDuration::FromSeconds(1)),
+           "TimeDuration > operator works");
+    Assert(TimeDuration::FromSeconds(1) <= TimeDuration::FromSeconds(2),
+           "TimeDuration <= operator works");
+    Assert(TimeDuration::FromSeconds(1) <= TimeDuration::FromSeconds(1),
+           "TimeDuration <= operator works");
+    Assert(!(TimeDuration::FromSeconds(2) <= TimeDuration::FromSeconds(1)),
+           "TimeDuration <= operator works");
+    Assert(TimeDuration::FromSeconds(2) >= TimeDuration::FromSeconds(1),
+           "TimeDuration >= operator works");
+    Assert(TimeDuration::FromSeconds(1) >= TimeDuration::FromSeconds(1),
+           "TimeDuration >= operator works");
+    Assert(!(TimeDuration::FromSeconds(1) >= TimeDuration::FromSeconds(2)),
+           "TimeDuration >= operator works");
+
+    TimeStamp ts;
+    Assert(ts.IsNull(), "Default TimeStamp value null");
+    
+    ts = TimeStamp::Now();
+    Assert(!ts.IsNull(), "TimeStamp time value non-null");
+    Assert((ts - ts).ToSeconds() == 0.0, "TimeStamp zero-length duration");
+
+    PR_Sleep(PR_SecondsToInterval(2));
+
+    TimeStamp ts2(TimeStamp::Now());
+    Assert(ts2 > ts, "TimeStamp > comparison");
+    Assert(!(ts > ts), "TimeStamp > comparison");
+    Assert(ts < ts2, "TimeStamp < comparison");
+    Assert(!(ts < ts), "TimeStamp < comparison");
+    Assert(ts <= ts2, "TimeStamp <= comparison");
+    Assert(ts <= ts, "TimeStamp <= comparison");
+    Assert(!(ts2 <= ts), "TimeStamp <= comparison");
+    Assert(ts2 >= ts, "TimeStamp >= comparison");
+    Assert(ts2 >= ts, "TimeStamp >= comparison");
+    Assert(!(ts >= ts2), "TimeStamp >= comparison");
+
+    // We can't be sure exactly how long PR_Sleep slept for. It should have
+    // slept for at least one second. We might have slept a lot longer due
+    // to process scheduling, but hopefully not more than 10 seconds.
+    td = ts2 - ts;
+    Assert(td.ToSeconds() > 1.0, "TimeStamp difference lower bound");
+    Assert(td.ToSeconds() < 20.0, "TimeStamp difference upper bound");
+    td = ts - ts2;
+    Assert(td.ToSeconds() < -1.0, "TimeStamp negative difference lower bound");
+    Assert(td.ToSeconds() > -20.0, "TimeStamp negative difference upper bound");
+
+    double resolution = TimeDuration::Resolution().ToSecondsSigDigits();
+    printf(" (platform timer resolution is ~%g s)\n", resolution);
+    Assert(0.000000001 < resolution, "Time resolution is sane");
+    // Don't upper-bound sanity check ... although NSPR reports 1ms
+    // resolution, it might be lying, so we shouldn't compare with it
+
+    return gFailCount > 0;
+}