Test for db upgrade skip

openlp/core/lib/db.py

@@ -62,7 +62,7 @@ def database_exists(url):
         create_database(engine.url)
         database_exists(engine.url)  #=> True
 
-    Borrowed from SQLAlchemy_Utils since we only need this one function.
+    Borrowed from SQLAlchemy_Utils (v0.32.14 )since we only need this one function.
     """
 
     url = copy(make_url(url))

tests/functional/openlp_core_lib/test_db.py

@@ -23,6 +23,9 @@
 Package to test the openlp.core.lib package.
 """
 import os
+import shutil
+
+from tempfile import mkdtemp
 from unittest import TestCase
 from unittest.mock import patch, MagicMock
 
@@ -30,13 +33,27 @@ from sqlalchemy.pool import NullPool
 from sqlalchemy.orm.scoping import ScopedSession
 from sqlalchemy import MetaData
 
-from openlp.core.lib.db import init_db, get_upgrade_op, delete_database
+from openlp.core.lib.db import init_db, get_upgrade_op, delete_database, upgrade_db
+from openlp.core.lib.projector import upgrade as pjlink_upgrade
 
 
 class TestDB(TestCase):
     """
     A test case for all the tests for the :mod:`~openlp.core.lib.db` module.
     """
+    def setUp(self):
+        """
+        Set up anything necessary for all tests
+        """
+        self.tmp_folder = mkdtemp(prefix='openlp_')
+
+    def tearDown(self):
+        """
+        Clean up
+        """
+        # Ignore errors since windows can have problems with locked files
+        shutil.rmtree(self.tmp_folder, ignore_errors=True)
+
     def test_init_db_calls_correct_functions(self):
         """
         Test that the init_db function makes the correct function calls
@@ -145,3 +162,17 @@ class TestDB(TestCase):
             MockedAppLocation.get_section_data_path.assert_called_with(test_plugin)
             mocked_delete_file.assert_called_with(test_location)
             self.assertFalse(result, 'The result of delete_file should be False (was rigged that way)')
+
+    @patch('tests.functional.openlp_core_lib.test_db.pjlink_upgrade')
+    def test_skip_db_upgrade_with_no_database(self, mocked_upgrade):
+        """
+        Test the upgrade_db function does not try to update a missing database
+        """
+        # GIVEN: Database URL that does not (yet) exist
+        url = 'sqlite:///{tmp}/test_db.sqlite'.format(tmp=self.tmp_folder)
+
+        # WHEN: We attempt to upgrade a non-existant database
+        upgrade_db(url, pjlink_upgrade)
+
+        # THEN: upgrade should NOT have been called
+        self.assertFalse(mocked_upgrade.called, 'Database upgrade function should NOT have been called')