Issue #10278: wallclock() cannot go backward, but two consecutive calls
may return the same time.
diff --git a/Lib/test/test_time.py b/Lib/test/test_time.py
index d34b870..685e821 100644
--- a/Lib/test/test_time.py
+++ b/Lib/test/test_time.py
@@ -334,7 +334,7 @@
     def test_wallclock(self):
         t1 = time.wallclock()
         t2 = time.wallclock()
-        self.assertGreater(t2, t1)
+        self.assertGreaterEqual(t2, t1)
 
         t1 = time.wallclock()
         time.sleep(0.1)