How can I test 'warnings' from testsuite?

[attn.steven.kuo at gmail.com]

On Sep 10, 7:08 am, billiejoex <gne... at gmail.com> wrote:
> Hi there,
> into a module of mine I 'warn' a message if a certain situation
> occurs:
>
> def add_anonymous_user(permissions=('r'):
>       if 'w' in p:
>           import warnings
>           warnings.warn("it's not rencommended assigning 'w'
> permission to anonymous user.", RuntimeWarning, stacklevel=2)
>
> I'd like to test such event from test suite ("fail test if warn is not
> raised") but don't know how.
>
> Any suggestion?



You can (temporarily) change warnings to exceptions
for the purposes of testing; see filterwarnings in
the warnings module.  E.g.,

import warnings
import unittest

def foo():
    warnings.warn("Foo", RuntimeWarning, stacklevel=2)

class testWarn(unittest.TestCase):
    def setUp(self):
        warnings.filterwarnings("error")
    def test_1(self):
        self.assertRaises(RuntimeWarning, foo)
    def tearDown(self):
        warnings.resetwarnings()

s = unittest.TestSuite()
s.addTest(unittest.makeSuite(testWarn))

if __name__ == '__main__':
    import sys
    sys.argv.append('-v')
    unittest.TextTestRunner(verbosity=2).run(s)


--
Hope this helps,
Steven