Fix name_scope test case bug (#20034)

test=develop
Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

python/paddle/fluid/tests/unittests/test_name_scope.py

@@ -43,3 +43,7 @@ class TestNameScope(unittest.TestCase):
                 self.assertEqual(op.desc.attr("op_namescope"), '/s4/')
             elif op.type == 'pow':
                 self.assertEqual(op.desc.attr("op_namescope"), '/s1_1/')
+
+
+if __name__ == "__main__":
+    unittest.main()