Url not parsed when testing a ModelViewSet
Solution 1:
When testing the view directly as you are doing, you are bypassing the url resolving/mapping logic. Therefore, you should pass the parameters as args/kwargs, in the end you are calling the foo function:
def test_foo(client: Client, db):
request = factory.post(f'/api/resource/1/foo/')
view = ResourceViewSet.as_view({'post': 'foo'})
response = view(request, pk=1)
If you'd like to test the whole stack, also the urls, I'd recommend you use the APIClient.