Python: handle sys.exit in unit tests?

Question

I have a management command that can do stuff, or can return a sys.exit().

I'm trying to handle the second case as follows in my unit tests:

 with self.assertRaises(SystemExit) as cm:
 call_command('geocode_practices', *args, **opts)
 self.assertEqual(cm.exception, 1)

But this gives me:

AssertionError: None != 1

What am I doing wrong?

Also, what's the best way to handle the different scenarios? At the moment my test will fail if the script does not exit.

• user2357112: Is this test expected to hit the "do stuff" case, or the sys.exit() case? And should this command be calling sys.exit() at all?
• bruno desthuilliers: Management command should be callable from other code, so raising a SystemExit is really a bad idea.
• Richard: @brunodesthuilliers thanks, how then should I handle an exit from a management command? (I want to fail gracefully in a case where there's no network connection.)
• bruno desthuilliers: @Richard docs.djangoproject.com/en/1.8/howto/custom-management-commands/…

Answer 1

Apparently the code inside your with block doesn't raise an exception. Note that sys.exit() just raises a SystemExit exception.

And even if it did, the exception will not compare equal to 1. If not None, the cm.exception attribute contains the exception instance, not a number.

• chepner: The odd thing is that if SystemExit isn't raised, the test should never even reach the call to assertEqual.