Fix some bad test running under PostgreSQL

from django.test import TestCase

from django.db import connection, models, migrations

from django.db.transaction import atomic

from django.db.utils import IntegrityError

from django.db.migrations.state import ProjectState

            "Pony",

            [

                ("id", models.AutoField(primary_key=True)),

                ("pink", models.BooleanField(default=True)),

                ("pink", models.IntegerField(default=3)),

                ("weight", models.FloatField()),

            ],

        )

            operation.database_forwards("test_alunto", editor, project_state, new_state)

        cursor.execute("INSERT INTO test_alunto_pony (id, pink, weight) VALUES (1, 1, 1)")

        with self.assertRaises(IntegrityError):

            with atomic():

                cursor.execute("INSERT INTO test_alunto_pony (id, pink, weight) VALUES (2, 1, 1)")

        cursor.execute("DELETE FROM test_alunto_pony")

        # And test reversal