Thank you @zhengli0060 for fixing rule9! The logic is correct and test went through pretty well. One small problem: in the uniittest (TestDAG2PAG), it's not common to use ad-hoc manual calls for the testcase, and i suggest to delete the "if name == "main__"". Otherwise I think it's ready to merge.

Thanks for Evie’s review. I’ve removed the new test case as suggested.

Thank you for checking again. Maybe there's a little understanding though: it's good to have the unittest case (def test_case_orient_rules), but to run the test, "if __name__ == '__main__': unittest.main()" would do the job rather than calling the tests separately. To keep the code clean and consisten with other test modules, I think L90-116 in the original pr is good to keep, but that L119-125 in the original pr should be removed.

Thank you for checking again. Maybe there's a little understanding though: it's good to have the unittest case (def test_case_orient_rules), but to run the test, "if __name__ == '__main__': unittest.main()" would do the job rather than calling the tests separately. To keep the code clean and consisten with other test modules, I think L90-116 in the original pr is good to keep, but that L119-125 in the original pr should be removed.

Thank you for your patient explanation. I’ve updated it accordingly.

Perfect!