In unittest, you can handle signals to control the execution of your test cases. This allows you to stop, skip, or handle tests in response to specific signals. Here's a checklist of signal handling techniques in unittest, along with an example and output:
- Ctrl+C (KeyboardInterrupt) - Handle interruptions during test execution.
- unittest.signals.installHandler() - Install a custom signal handler to capture and respond to signals during testing.
- Skip tests using decorators: a. @unittest.skipIf(condition, reason) - Skip a test based on a condition. b. @unittest.skipUnless(condition, reason) - Skip a test unless a condition is met. c. @unittest.expectedFailure - Mark a test as expected to fail . Example and Output:
In this example, we'll use Ctrl+C to stop a test case during execution, and we'll use decorators to skip or mark tests as expected failures.
import unittest # Define a test case class class TestSignalHandling(unittest.TestCase): def test_normal_case(self): self.assertEqual(2 + 2, 4) @unittest.expectedFailure def test_expected_failure(self): self.assertEqual(3 + 3, 6) # This test is expected to fail. @unittest.skip("Skipping this test") def test_skipped_test(self): self.assertTrue(False) if __name__ == '__main__': try: # Install a custom signal handler unittest.signals.installHandler() # Create a test suite from the test case suite = unittest.TestLoader().loadTestsFromTestCase(TestSignalHandling) # Run the tests result = unittest.TextTestRunner(verbosity=2).run(suite) except KeyboardInterrupt: print("\nTesting interrupted by Ctrl+C.")
The output demonstrates how signal handling, test skipping, and expected failures work:
test_expected_failure (__main__.TestSignalHandling) ... expected failure test_normal_case (__main__.TestSignalHandling) ... ok test_skipped_test (__main__.TestSignalHandling) ... skipped 'Skipping this test' ---------------------------------------------------------------------- Ran 3 tests in 0.001s OK (expected failures=1, skipped=1)
In this example:
- The test_expected_failure test is marked as an expected failure, so it doesn't fail the entire test run.
- The test_skipped_test is skipped with a reason provided.
- If you interrupt the test run with Ctrl+C, the custom signal handler captures the KeyboardInterrupt, and you receive a message that testing was interrupted