Why isn't assertRaises catching my Attribute Error using python unittest?

Question

I\'m trying to run this test: self.assertRaises(AttributeError, branch[0].childrennodes), and branch[0] does not have an attribute childrenno

Answer 1

I think its because assert raises only accepts a callable. It evalutes to see if the callable raises an exception, not if the statement itself does.

self.assertRaises(AttributeError, getattr, branch[0], "childrennodes")

should work.

EDIT:

As THC4k correctly says it gathers the statements at collection time and will error then, not at testing time.

Also this is a reason why I like nose, it has a decorator (raises) that is useful and clearer for these kind of tests.

@raises(AttributeError)
def test_1(self)
    branch[0].childrennodes