diff --git a/Lib/unittest.py b/Lib/unittest.py
index d781354..5858d89 100644
--- a/Lib/unittest.py
+++ b/Lib/unittest.py
@@ -1567,7 +1567,7 @@
                 return
             if len(args) > 0:
                 self.testNames = args
-                if os.path.splitext(os.path.basename(__file__))[0] == 'unitest':
+                if sys.modules['unittest'] is sys.modules['__main__']:
                     self.module = None
             else:
                 self.testNames = (self.defaultTest,)