Reorganized backends tests.

tests/db_utils/tests.py

@@ -0,0 +1,49 @@
+"""Tests for django.db.utils."""
+import unittest
+
+from django.core.exceptions import ImproperlyConfigured
+from django.db import DEFAULT_DB_ALIAS, connection
+from django.db.utils import ConnectionHandler, ProgrammingError, load_backend
+from django.test import SimpleTestCase, TestCase
+
+
+class ConnectionHandlerTests(SimpleTestCase):
+
+    def test_connection_handler_no_databases(self):
+        """Empty DATABASES setting defaults to the dummy backend."""
+        DATABASES = {}
+        conns = ConnectionHandler(DATABASES)
+        self.assertEqual(conns[DEFAULT_DB_ALIAS].settings_dict['ENGINE'], 'django.db.backends.dummy')
+        msg = (
+            'settings.DATABASES is improperly configured. Please supply the '
+            'ENGINE value. Check settings documentation for more details.'
+        )
+        with self.assertRaisesMessage(ImproperlyConfigured, msg):
+            conns[DEFAULT_DB_ALIAS].ensure_connection()
+
+
+class DatabaseErrorWrapperTests(TestCase):
+
+    @unittest.skipUnless(connection.vendor == 'postgresql', 'PostgreSQL test')
+    def test_reraising_backend_specific_database_exception(self):
+        cursor = connection.cursor()
+        msg = 'table "X" does not exist'
+        with self.assertRaisesMessage(ProgrammingError, msg) as cm:
+            cursor.execute('DROP TABLE "X"')
+        self.assertNotEqual(type(cm.exception), type(cm.exception.__cause__))
+        self.assertIsNotNone(cm.exception.__cause__)
+        self.assertIsNotNone(cm.exception.__cause__.pgcode)
+        self.assertIsNotNone(cm.exception.__cause__.pgerror)
+
+
+class LoadBackendTests(SimpleTestCase):
+
+    def test_load_backend_invalid_name(self):
+        msg = (
+            "'foo' isn't an available database backend.\n"
+            "Try using 'django.db.backends.XXX', where XXX is one of:\n"
+            "    'mysql', 'oracle', 'postgresql', 'sqlite3'"
+        )
+        with self.assertRaisesMessage(ImproperlyConfigured, msg) as cm:
+            load_backend('foo')
+        self.assertEqual(str(cm.exception.__cause__), "No module named 'foo'")