I am relatively new to Python and want to use a assertRaises
test to check for a ValidationError
, which works ok. However, I have many ValidationError
s and I want to make sure the right one is returned. I figured I could pass something into assertRaises
but it doesn't look like I can, so I figured I would just do an assertTrue
and check the exception message. However, I don't know how to access it. Is this even a good way to approach this issue? thanks.
class DailyEntriesTests(TestCase): def test_cant_have_ip_and_user(self): u = createUser(False) de = createDailyEntry(u, "1.1.1.1", 1) with self.assertRaises(ValidationError) as cm: de.full_clean() # this line bombs - message doesn't exist. I also tried "error_code" like I saw in the documentation, but that doesn't work print(cm.exception.message) self.assertTrue(cm.exception.message.contains("Both"))
There are two ways you can use assertRaises: using keyword arguments. Just pass the exception, the callable function and the parameters of the callable function as keyword arguments that will elicit the exception. Make a function call that should raise the exception with a context.
Just trick it to always skip with the argument True : @skipIf(True, "I don't want to run this test yet") def test_something(): ... If you are looking to simply not run certain test files, the best way is probably to use fab or other tool and run particular tests.
The best base class for most tests is django. test. TestCase. This test class creates a clean database before its tests are run, and runs every test function in its own transaction. The class also owns a test Client that you can use to simulate a user interacting with the code at the view level.
self. client , is the built-in Django test client. This isn't a real browser, and doesn't even make real requests. It just constructs a Django HttpRequest object and passes it through the request/response process - middleware, URL resolver, view, template - and returns whatever Django produces.
Since the question is related to Django, you could also use the assertRaisesMessage
context manager when inheriting from django's TestCase.
from django.test import TestCase class ExceptionTest(TestCase): def test_call_raises_exception_with_custom_message(self): with self.assertRaisesMessage(Exception, 'My custom message!'): call_that_causes_exception()
Note: The assertRaisesMessage
manager does an in
lookup on the exceptions message: Say your exception raises "My custom message!", asserting for "custom message" passes. Bear this in mind especially if you have multiple (custom) exceptions with similar messages.
(E.g. two different exceptions raising "My custom message! Further details..." and "My custom message! No details." would both pass an assert for "My custom message!").
You can just use assertRaisesRegexp
.
with self.assertRaisesRegexp(ValidationError, "Both"): de.full_clean()
When you use it as a context manager the 2nd argument is a regular expression to search through the exception's string representation.
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