Make it possible to run this test stand-alone.
diff --git a/Lib/test/test_frozen.py b/Lib/test/test_frozen.py
index e47bb64..3c9fab3 100644
--- a/Lib/test/test_frozen.py
+++ b/Lib/test/test_frozen.py
@@ -38,3 +38,6 @@
 
 def test_main():
     run_unittest(FrozenTests)
+
+if __name__ == "__main__":
+    test_main()