Fixed #25172 -- Fixed check framework to work with multiple databases.

tests/check_framework/test_multi_db.py

@@ -0,0 +1,43 @@
+from django.db import connections, models
+from django.test import TestCase, mock
+from django.test.utils import override_settings
+
+from .tests import IsolateModelsMixin
+
+
+class TestRouter(object):
+    """
+    Routes to the 'other' database if the model name starts with 'Other'.
+    """
+    def allow_migrate(self, db, app_label, model=None, **hints):
+        return db == ('other' if model._meta.verbose_name.startswith('other') else 'default')
+
+
+@override_settings(DATABASE_ROUTERS=[TestRouter()])
+class TestMultiDBChecks(IsolateModelsMixin, TestCase):
+    multi_db = True
+
+    def _patch_check_field_on(self, db):
+        return mock.patch.object(connections[db].validation, 'check_field')
+
+    def test_checks_called_on_the_default_database(self):
+        class Model(models.Model):
+            field = models.CharField(max_length=100)
+
+        model = Model()
+        with self._patch_check_field_on('default') as mock_check_field_default:
+            with self._patch_check_field_on('other') as mock_check_field_other:
+                model.check()
+                self.assertTrue(mock_check_field_default.called)
+                self.assertFalse(mock_check_field_other.called)
+
+    def test_checks_called_on_the_other_database(self):
+        class OtherModel(models.Model):
+            field = models.CharField(max_length=100)
+
+        model = OtherModel()
+        with self._patch_check_field_on('other') as mock_check_field_other:
+            with self._patch_check_field_on('default') as mock_check_field_default:
+                model.check()
+                self.assertTrue(mock_check_field_other.called)
+                self.assertFalse(mock_check_field_default.called)