Method startTestRun() is always called for the TestResult object implicitly created by TestCase.defaultTestResult() when no TestResult object is passed to TestCase.run(). But method stopTestRun() is not always called in pair with startTestRun() for skipped tests. It is only called if SkipTest was raised directly or indirectly (via skipTest()). It is not called if a skipping decorator (@skip, @skipIf, @skipUnless) was used for a method or a class.