Learn

Sometimes we have a test that we know will fail. This could happen when a feature has a known bug or is designed to fail on purpose. In this case, we wouldn’t want an expected failure to cloud our test results. Rather than simply skipping the test, unittest provides a way to mark tests as expected failures. Expected failures are counted as passed in our test results. If the test passes when we expected it to fail, then it is marked as failed in test results.

To setup a test to have an expected failure, we can use the expectedFailure decorator. Let’s consider the following example:

class FeatureTests(unittest.TestCase): @unittest.expectedFailure def test_broken_feature(self): raise Exception("This test is going to fail")

The expectedFailure decorator takes no arguments. The test in the example will always fail because an exception was raised during test execution. When run, we get the following output:

x ---------------------------------------------------------------------- Ran 1 test in 0.000s OK (expected failures=1)

The test failure did not cause any failures in our test results because it was marked as expected. Let’s do the same for some of our Small World Air tests.

Instructions

1.

The monitors in front of passenger seats on Small World planes contain a customer feedback portal. The class CustomerFeedbackTests has tests for both the survey and the complaint form.

We can find the tests in tests.py and the functions that perform feedback tasks in feedback.py. Take some time to get acquainted with the program. Run the code to move on!

2.

Looks like test_survey_form() caught a bug in the customer survey form! It’s best not to have this test fail every day while we wait for the bug to get fixed.

Use the expectedFailure decorator to mark this test as an expected failure!

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