'Invoke the view with a request missing a field and assert correctness.
The request will be a POST request from the given `user`, with POST
fields taken from `fields` minus the entry specified by `omit_field`.
The response should have a 400 (bad request) status code and specify
the invalid field and an error message, and the Zendesk API should not
have been invoked.'

def _test_bad_request_omit_field(self, user, fields, omit_field, zendesk_mock_class, datadog_mock):

    filtered_fields = {k: v for (k, v) in fields.items() if (k != omit_field)}
    resp = self._build_and_run_request(user, filtered_fields)
    self._assert_bad_request(resp, omit_field, zendesk_mock_class, datadog_mock)
