Add ``if __name__ == '__main__'`` to some test files where it didn't take a lot
of effort to do so.
diff --git a/Lib/test/test_lib2to3.py b/Lib/test/test_lib2to3.py
index beda695..161b9dd 100644
--- a/Lib/test/test_lib2to3.py
+++ b/Lib/test/test_lib2to3.py
@@ -13,3 +13,7 @@
 
 def test_main():
     run_unittest(suite())
+
+
+if __name__ == '__main__':
+    test_main()