from django.db import DatabaseError, IntegrityError, transaction

from django.test import TestCase

from .models import Counter, InheritedCounter, ProxyCounter, SubCounter, 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

        msg = "Cannot force both insert and updating in model saving."

        with self.assertRaisesMessage(ValueError, msg):

            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)

        msg = "Cannot force an update in save() with no primary key."

        with self.assertRaisesMessage(ValueError, msg):

            with transaction.atomic():

                c1.save(force_update=True)

        c1.save(force_insert=True)

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

        c.value = 5

        with self.assertRaises(IntegrityError):

            with transaction.atomic():

                c.save(force_insert=True)

        # 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)

        msg = "Forced update did not affect any rows."

        with self.assertRaisesMessage(DatabaseError, msg):

            with transaction.atomic():

                obj.save(force_update=True)

class InheritanceTests(TestCase):

    def test_force_update_on_inherited_model(self):

        a = InheritedCounter(name="count", value=1, tag="spam")

        a.save()

        a.save(force_update=True)

    def test_force_update_on_proxy_model(self):

        a = ProxyCounter(name="count", value=1)

        a.save()

        a.save(force_update=True)

    def test_force_update_on_inherited_model_without_fields(self):

        """

        Issue 13864: force_update fails on subclassed models, if they don't

        specify custom fields.

        """

        a = SubCounter(name="count", value=1)

        a.save()

        a.value = 2

        a.save(force_update=True)