Unittest causing sys.exit()

Question

No matter what I do sys.exit() is called by unittest, even the most trivial examples. I can't tell if my install is messed up or what is going on.

IDLE 1.2.2      ==== No Subprocess ====
>>> import unittest
>>> 
>>> class Test(unittest.TestCase):
        def testA(self):
         a = 1
         self.assertEqual(a,1)

>>> unittest.main()
option -n not recognized
Usage: idle.pyw [options] [test] [...]

Options:
  -h, --help       Show this message
  -v, --verbose    Verbose output
  -q, --quiet      Minimal output

 Examples:
   idle.pyw                               - run default set of tests
   idle.pyw MyTestSuite                   - run suite 'MyTestSuite'
   idle.pyw MyTestCase.testSomething      - run MyTestCase.testSomething
   idle.pyw MyTestCase                    - run all 'test*' test methods
                                           in MyTestCase

Traceback (most recent call last):
  File "<pyshell#7>", line 1, in <module>
    unittest.main()
  File "E:\Python25\lib\unittest.py", line 767, in __init__
    self.parseArgs(argv)
  File "E:\Python25\lib\unittest.py", line 796, in parseArgs
    self.usageExit(msg)
  File "E:\Python25\lib\unittest.py", line 773, in usageExit
    sys.exit(2)
SystemExit: 2
>>>

Answer 1

Don't try to run unittest.main() from IDLE. It's trying to access sys.argv, and it's getting the args that IDLE was started with. Either run your tests in a different way from IDLE, or call unittest.main() in its own Python process.

Answer 2

Your example is exiting on my install too. I can make it execute the tests and stay within Python by changing

unittest.main()

to

unittest.TextTestRunner().run(unittest.TestLoader().loadTestsFromTestCase(Test))

More information is available here in the Python Library Reference.

Answer 3

Pop open the source code to unittest.py. unittest.main() is hard-coded to call sys.exit() after running all tests. Use TextTestRunner to run test suites from the prompt.

Answer 4

try:
    sys.exit()
except SystemExit:
    print('Simple as that, but you should really use a TestRunner instead')

Answer 5

In new Python 2.7 release, unittest.main() has a new argument.

If 'exit' is set to False, sys.exit() is not called during the execution of unittest.main().