from django.core.exceptions import FieldError

from django.test import TestCase

from .models.default_related_name import Author, Book, Editor

class DefaultRelatedNameTests(TestCase):

    @classmethod

    def setUpTestData(cls):

        cls.author = Author.objects.create(first_name="Dave", last_name="Loper")

        cls.editor = Editor.objects.create(

            name="Test Editions", bestselling_author=cls.author

        )

        cls.book = Book.objects.create(title="Test Book", editor=cls.editor)

        cls.book.authors.add(cls.author)

    def test_no_default_related_name(self):

        self.assertEqual(list(self.author.editor_set.all()), [self.editor])

    def test_default_related_name(self):

        self.assertEqual(list(self.author.books.all()), [self.book])

    def test_default_related_name_in_queryset_lookup(self):

        self.assertEqual(Author.objects.get(books=self.book), self.author)

    def test_model_name_not_available_in_queryset_lookup(self):

        msg = "Cannot resolve keyword 'book' into field."

        with self.assertRaisesMessage(FieldError, msg):

            Author.objects.get(book=self.book)

    def test_related_name_overrides_default_related_name(self):

        self.assertEqual(list(self.editor.edited_books.all()), [self.book])

    def test_inheritance(self):

        # model_options is the name of the application for this test.

        self.assertEqual(list(self.book.model_options_bookstores.all()), [])

    def test_inheritance_with_overridden_default_related_name(self):

        self.assertEqual(list(self.book.editor_stores.all()), [])