from datetime import datetime

from django.test import TestCase

from .models import Article, Reporter, Writer

class M2MIntermediaryTests(TestCase):

    def test_intermediary(self):

        r1 = Reporter.objects.create(first_name="John", last_name="Smith")

        r2 = Reporter.objects.create(first_name="Jane", last_name="Doe")

        a = Article.objects.create(

            headline="This is a test", pub_date=datetime(2005, 7, 27)

        )

        w1 = Writer.objects.create(reporter=r1, article=a, position="Main writer")

        w2 = Writer.objects.create(reporter=r2, article=a, position="Contributor")

        self.assertQuerysetEqual(

            a.writer_set.select_related().order_by("-position"),

            [

                ("John Smith", "Main writer"),

                ("Jane Doe", "Contributor"),

            ],

            lambda w: (str(w.reporter), w.position),

        )

        self.assertEqual(w1.reporter, r1)

        self.assertEqual(w2.reporter, r2)

        self.assertEqual(w1.article, a)

        self.assertEqual(w2.article, a)

        self.assertQuerysetEqual(

            r1.writer_set.all(),

            [("John Smith", "Main writer")],

            lambda w: (str(w.reporter), w.position),

        )