python runtime_error ai_generated true

ResourceWarning: unclosed file <_io.TextIOWrapper name='/tmp/test.log' mode='w' encoding='UTF-8'>

ID: python/unittest-teardown-not-called-on-skip

Also available as: JSON · Markdown · 中文
80%Fix Rate
83%Confidence
0Evidence
2024-07-30First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.8 active — — —
3.12 active — — —

Root Cause

A test calls self.skipTest() inside setUp after opening a resource, so tearDown never runs and the resource leaks; or setUpClass raised and tearDownClass is skipped.

generic

中文

测试在 setUp 中打开资源后调用 self.skipTest()，导致 tearDown 从未运行、资源泄漏；或 setUpClass 抛出异常后 tearDownClass 被跳过。

Workarounds

  1. 95% success 
    class TestX(unittest.TestCase):
    def setUp(self):
        self.f = open('/tmp/test.log', 'w')
        self.addCleanup(self.f.close)
        if not condition:
            self.skipTest('condition not met')
  2. 92% success 
    def test_x(self):
    with open('/tmp/test.log', 'w') as f:
        ...
    # file closed even if test fails

Dead Ends

Common approaches that don't work:

  1. 80% fail

    Hides the leak; file descriptors accumulate across a large test suite and eventually cause EMFILE.

  2. 60% fail

    Skips before any setup runs, but other tests that do open resources still leak.