Altered test introduced in f19a3669 for the sake of readability. refs #14786

        Regression test for #14786 -- Test that field values are not prepared

        twice in get_db_prep_lookup().

        """

        prepare_count = [0]

        class NoopField(models.TextField):

            def __init__(self, *args, **kwargs):

                self.prep_value_count = 0

                super(NoopField, self).__init__(*args, **kwargs)

            def get_prep_value(self, value):

                prepare_count[0] += 1

                self.prep_value_count += 1

                return super(NoopField, self).get_prep_value(value)

        field = NoopField()

        field.get_db_prep_lookup('exact', 'TEST', connection=connection, prepared=False)

        self.assertEqual(prepare_count[0], 1)

        field.get_db_prep_lookup(

            'exact', 'TEST', connection=connection, prepared=False

        )

        self.assertEqual(field.prep_value_count, 1)