Unexpected Success not handled gracefully

[silkehorn]

The following script fails:

import unittest
import xmlrunner


class ExampleTestCase(unittest.TestCase):
    @unittest.expectedFailure
    def test_unexpected_success(self):
        self.assertTrue(True) 

if __name__ == "__main__":
    # Run tests with xmlrunner and output the results as XML
    with open('test-reports/results.xml', 'wb') as output:
        unittest.main(testRunner=xmlrunner.XMLTestRunner(output=output))

This is the output:

Running tests...
----------------------------------------------------------------------
u
======================================================================
Traceback (most recent call last):
  File "simpletest.py", line 13, in <module>
    unittest.main(testRunner=xmlrunner.XMLTestRunner(output=output))
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/unittest/main.py", line 102, in __init__
    self.runTests()
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/unittest/main.py", line 274, in runTests
    self.result = testRunner.run(self.test)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/xmlrunner/runner.py", line 72, in run
    result.printErrors()
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/unittest/runner.py", line 149, in printErrors
    self.stream.writeln(f"UNEXPECTED SUCCESS: {self.getDescription(test)}")
                                               ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/unittest/runner.py", line 47, in getDescription
    doc_first_line = test.shortDescription()
                     ^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'tuple' object has no attribute 'shortDescription'

It seems that unittest expects a scalar test, but gets a tuple (test, "unexpected success").