how to write django test meant to fail?
If you're expecting Thing(name='1234') to raise an exception, there are two ways to deal with this.
One is to use Django's assertRaises (actually from unittest/unittest2):
def mytest(self): self.assertRaises(FooException, Thing, name='1234')
This fails unless Thing(name='1234') raises a FooException error. Another way is to catch the expected exception and raise one if it doesn't happen, like this:
def mytest(self): try: thing = Thing(name='1234') self.fail("your message here") except FooException: pass
Obviously, replace the FooException with the one you expect to get from creating the object with too long a string. ValidationError?
A third option (as of Python 2.7) is to use assertRaises as a context manager, which makes for cleaner, more readable code:
def mytest(self): with self.assertRaises(FooException): thing = Thing(name='1234')
Sadly, this doesn't allow for custom test failure messages, so document your tests well. See https://hg.python.org/cpython/file/2.7/Lib/unittest/case.py#l97 for more details.
I am currently using the expectedFailure
decorator from unittest. That works as advertised: Fails when there is no error, passes when there is a failure.
I use expectedFailure
to verify that my custom assert-routines actually work and not just rubberstamp everything OK.
import unittestfrom django.test import TestCaseclass EmojiTestCase(TestCase): @unittest.expectedFailure def testCustomAssert(self): self.assertHappyFace(':(') # must fail.
But prints a warning-message during testing. I use it with Django and Nose. Which others have seen, too.
/usr/lib64/python3.4/unittest/case.py:525: RuntimeWarning: TestResult has no addExpectedFailure method, reporting as passes RuntimeWarning)
I came here to find a better solution, but found none. So I at least wanted to tell others that come what I've been working with.
In my previous project i had to do something like test driven development, so i have written some test case which must catch certain types of error. If it don't gets the error then i have messed up something. Here i share my code.
from django.test import TestCasefrom django.contrib.auth.models import Userclass ModelTest(TestCase):def test_create_user_with_email(self): with self.assertRaises(TypeError): email = "ah@gmail.com" password = 'testpass1' user = User.objects.create_user( email = email, password = password,) self.assertEqual(user.email, email) self.assertTrue(user.check_password(password))
You can see i have tried to create a user with email and password but default Django user model need "username" and "password" arguments to create user. So here my testcase must raise "TypeError". And that what i tried to do here.