'check_finders() concatenates all errors.'

def test_check_finders(self):

    error1 = Error('1')
    error2 = Error('2')
    error3 = Error('3')
    def get_finders():
        class Finder1(BaseFinder, ):
            def check(self, **kwargs):
                return [error1]
        class Finder2(BaseFinder, ):
            def check(self, **kwargs):
                return []
        class Finder3(BaseFinder, ):
            def check(self, **kwargs):
                return [error2, error3]
        class Finder4(BaseFinder, ):
            pass
        return [Finder1(), Finder2(), Finder3(), Finder4()]
    with mock.patch('django.contrib.staticfiles.checks.get_finders', get_finders):
        errors = check_finders(None)
        self.assertEqual(errors, [error1, error2, error3])
