from django.test import TestCase, TransactionTestCase
from django.db import connection
from django.db.migrations.loader import MigrationLoader
from django.db.migrations.recorder import MigrationRecorder


class RecorderTests(TestCase):
    """
    Tests recording migrations as applied or not.
    """

    def test_apply(self):
        """
        Tests marking migrations as applied/unapplied.
        """
        recorder = MigrationRecorder(connection)
        self.assertEqual(
            recorder.applied_migrations(),
            set(),
        )
        recorder.record_applied("myapp", "0432_ponies")
        self.assertEqual(
            recorder.applied_migrations(),
            set([("myapp", "0432_ponies")]),
        )
        recorder.record_unapplied("myapp", "0432_ponies")
        self.assertEqual(
            recorder.applied_migrations(),
            set(),
        )


class LoaderTests(TransactionTestCase):
    """
    Tests the disk and database loader, and running through migrations
    in memory.
    """

    def test_load(self):
        """
        Makes sure the loader can load the migrations for the test apps,
        and then render them out to a new AppCache.
        """
        # Load and test the plan
        migration_loader = MigrationLoader(connection)
        self.assertEqual(
            migration_loader.graph.forwards_plan(("migrations", "0002_second")),
            [("migrations", "0001_initial"), ("migrations", "0002_second")],
        )
        # Now render it out!
        project_state = migration_loader.graph.project_state(("migrations", "0002_second"))
        self.assertEqual(len(project_state.models), 2)

        author_state = project_state.models["migrations", "author"]
        self.assertEqual(
            [x for x, y in author_state.fields],
            ["id", "name", "slug", "age", "rating"]
        )

        book_state = project_state.models["migrations", "book"]
        self.assertEqual(
            [x for x, y in book_state.fields],
            ["id", "author"]
        )