from django.db import transaction, IntegrityError, DatabaseError

from django.test import TestCase

from models import Counter, WithCustomPK

class ForceTests(TestCase):

    def test_force_update(self):

        c = Counter.objects.create(name="one", value=1)

        # The normal case

        c.value = 2

        c.save()

        # Same thing, via an update

        c.value = 3

        c.save(force_update=True)

        # Won't work because force_update and force_insert are mutually

        # exclusive

        c.value = 4

        self.assertRaises(ValueError, c.save, force_insert=True, force_update=True)

        # Try to update something that doesn't have a primary key in the first

        # place.

        c1 = Counter(name="two", value=2)

        self.assertRaises(ValueError, c1.save, force_update=True)

        c1.save(force_insert=True)

        # Won't work because we can't insert a pk of the same value.

        sid = transaction.savepoint()

        c.value = 5

        self.assertRaises(IntegrityError, c.save, force_insert=True)

        transaction.savepoint_rollback(sid)

        # Trying to update should still fail, even with manual primary keys, if

        # the data isn't in the database already.

        obj = WithCustomPK(name=1, value=1)

        self.assertRaises(DatabaseError, obj.save, force_update=True)