from django.test import TestCase

from django.core.exceptions import FieldError

from models import User, Poll, Choice

class ReverseLookupTests(TestCase):

    def setUp(self):

        john = User.objects.create(name="John Doe")

        jim = User.objects.create(name="Jim Bo")

        first_poll = Poll.objects.create(

            question="What's the first question?",

            creator=john

        )

        second_poll = Poll.objects.create(

            question="What's the second question?",

            creator=jim

        )

        new_choice = Choice.objects.create(

            poll=first_poll,

            related_poll=second_poll,

            name="This is the answer."

        )

    def test_reverse_by_field(self):

        u1 = User.objects.get(

            poll__question__exact="What's the first question?"

        )

        self.assertEqual(u1.name, "John Doe")

        u2 = User.objects.get(

            poll__question__exact="What's the second question?"

        )

        self.assertEqual(u2.name, "Jim Bo")

    def test_reverse_by_related_name(self):

        p1 = Poll.objects.get(poll_choice__name__exact="This is the answer.")

        self.assertEqual(p1.question, "What's the first question?")

        p2 = Poll.objects.get(

            related_choice__name__exact="This is the answer.")

        self.assertEqual(p2.question, "What's the second question?")

    def test_reverse_field_name_disallowed(self):

        """

        If a related_name is given you can't use the field name instead

        """

        self.assertRaises(FieldError, Poll.objects.get,

            choice__name__exact="This is the answer")