Debug School

rakesh kumar
rakesh kumar

Posted on

Signal Handling of test cases in unittest

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:

  1. Ctrl+C (KeyboardInterrupt) - Handle interruptions during test execution.
  2. unittest.signals.installHandler() - Install a custom signal handler to capture and respond to signals during testing.
  3. 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)

    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):

if __name__ == '__main__':
        # Install a custom signal handler

        # 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.")
Enter fullscreen mode Exit fullscreen mode

Expected Output:

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)
Enter fullscreen mode Exit fullscreen mode

In this example:

  1. The test_expected_failure test is marked as an expected failure, so it doesn't fail the entire test run.
  2. The test_skipped_test is skipped with a reason provided.
  3. 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


Top comments (0)