Add upgrade test coverage

Adding additional test upgrade coverage. This implementation
tests things like the is_migration_needed flag. In the future
we can also add support for MySQL functional coverage as well.

Change-Id: I9386d1bfbfee1fe8ff41859520cdbe94381ee3fd

designate/storage/sqlalchemy/alembic.ini

@@ -2,7 +2,7 @@
 
 [alembic]
 # path to migration scripts
-script_location = alembic
+script_location = %(here)s/alembic
 
 # template used to generate migration file names; The default value is %%(rev)s_%%(slug)s
 # Uncomment the line below if you want the files to be prepended with date and time

designate/storage/sqlalchemy/alembic/env.py

@@ -42,12 +42,12 @@ def run_migrations_offline() -> None:
     script output.
 
     """
-    url = config.get_main_option("sqlalchemy.url")
+    url = config.get_main_option('sqlalchemy.url')
     context.configure(
         url=url,
         target_metadata=target_metadata,
         literal_binds=True,
-        dialect_opts={"paramstyle": "named"},
+        dialect_opts={'paramstyle': 'named'},
     )
 
     with context.begin_transaction():
@@ -61,16 +61,32 @@ def run_migrations_online() -> None:
     and associate a connection with the context.
 
     """
-    connectable = engine_from_config(
-        config.get_section(config.config_ini_section),
-        prefix="sqlalchemy.",
-        poolclass=pool.NullPool,
-    )
+    connectable = config.attributes.get('connection', None)
+    if connectable is None:
+        # only create Engine if we don't have a Connection from the outside
+        connectable = engine_from_config(
+            config.get_section(config.config_ini_section),
+            prefix='sqlalchemy.',
+            poolclass=pool.NullPool,
+        )
+        with connectable.connect() as connection:
+            context.configure(
+                connection=connection,
+                target_metadata=target_metadata,
+                render_as_batch=True,
+                transactional_ddl=True,
+                transaction_per_migration=True,
+            )
 
-    with connectable.connect() as connection:
+            with context.begin_transaction():
+                context.run_migrations()
+    else:
         context.configure(
-            connection=connection, target_metadata=target_metadata,
-            transactional_ddl=True, transaction_per_migration=True
+            connection=connectable,
+            target_metadata=target_metadata,
+            render_as_batch=True,
+            transactional_ddl=True,
+            transaction_per_migration=True,
         )
 
         with context.begin_transaction():

designate/tests/test_storage/test_migration.py

@@ -0,0 +1,175 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+# Based on Nova's test_migrations.py
+
+
+import os
+
+from unittest import mock
+
+from alembic import command as alembic_api
+from alembic import config as alembic_config
+from alembic import script as alembic_script
+from oslo_db.sqlalchemy import enginefacade
+from oslo_db.sqlalchemy import test_fixtures
+from oslo_log import log as logging
+
+from designate.storage import sqlalchemy
+from designate.storage.sqlalchemy.alembic import legacy_utils
+from designate import tests
+
+
+LOG = logging.getLogger(__name__)
+ALEMBIC_PATH = os.path.join(
+    os.path.dirname(sqlalchemy.__file__), 'alembic.ini'
+)
+
+
+class DesignateMigrationsWalk(
+    test_fixtures.OpportunisticDBTestMixin, tests.TestCase,
+):
+    # Migrations can take a long time, particularly on underpowered CI nodes.
+    # Give them some breathing room.
+    TIMEOUT_SCALING_FACTOR = 4
+
+    def setUp(self):
+        super().setUp()
+        self.engine = enginefacade.writer.get_engine()
+        self.config = alembic_config.Config(ALEMBIC_PATH)
+        self.init_version = 'c9f427f7180a'
+
+    def _migrate_up(self, connection, revision):
+        if revision == self.init_version:  # no tests for the initial revision
+            alembic_api.upgrade(self.config, revision)
+            return
+
+        self.assertIsNotNone(
+            getattr(self, '_check_%s' % revision, None),
+            (
+                'DB Migration %s does not have a test; you must add one'
+            ) % revision,
+        )
+
+        pre_upgrade = getattr(self, '_pre_upgrade_%s' % revision, None)
+        if pre_upgrade:
+            pre_upgrade(connection)
+
+        alembic_api.upgrade(self.config, revision)
+
+        post_upgrade = getattr(self, '_check_%s' % revision, None)
+        if post_upgrade:
+            post_upgrade(connection)
+
+    def _check_867a331ce1fc(self, connection):
+        pass
+
+    def _check_d9a1883e93e9(self, connection):
+        pass
+
+    def _check_bfcfc4a07487(self, connection):
+        pass
+
+    def _check_f9f969f9d85e(self, connection):
+        pass
+
+    def _check_a69b45715cc1(self, connection):
+        pass
+
+    def _check_0bcf910ea823(self, connection):
+        pass
+
+    def _check_d04819112169(self, connection):
+        pass
+
+    def _check_304d41c3847a(self, connection):
+        pass
+
+    def _check_15b34ff3ecb8(self, connection):
+        pass
+
+    def _check_7977deaa5167(self, connection):
+        pass
+
+    def _check_93a00a815f07(self, connection):
+        pass
+
+    def _check_b8999fd10721(self, connection):
+        pass
+
+    def _check_91eb1eb7c882(self, connection):
+        pass
+
+    def _check_e5e2199ed76e(self, connection):
+        pass
+
+    def _check_b20189fd288e(self, connection):
+        pass
+
+    def _check_a005af3aa38e(self, connection):
+        pass
+
+    def test_single_base_revision(self):
+        script = alembic_script.ScriptDirectory.from_config(self.config)
+        self.assertEqual(1, len(script.get_bases()))
+
+    def test_walk_versions(self):
+        with self.engine.begin() as connection:
+            self.config.attributes['connection'] = connection
+            script = alembic_script.ScriptDirectory.from_config(self.config)
+            revisions = [x.revision for x in script.walk_revisions()]
+
+            # for some reason, 'walk_revisions' gives us the revisions in
+            # reverse chronological order, so we have to invert this
+            revisions.reverse()
+            self.assertEqual(revisions[0], self.init_version)
+
+            for revision in revisions:
+                LOG.info('Testing revision %s', revision)
+                self._migrate_up(connection, revision)
+
+    def test_is_migration_needed(self):
+        with self.engine.begin() as connection:
+            self.config.attributes['connection'] = connection
+            script = alembic_script.ScriptDirectory.from_config(self.config)
+            revisions = [x.revision for x in script.walk_revisions()]
+
+            # for some reason, 'walk_revisions' gives us the revisions in
+            # reverse chronological order, so we have to invert this
+            revisions.reverse()
+            self.assertEqual(revisions[0], self.init_version)
+
+            for revision in revisions:
+                LOG.info('Testing revision %s', revision)
+
+                # Let's stop after the first revision
+                # without is_migration_needed.
+                if revision == 'b20189fd288e':
+                    break
+                self._migrate_up(connection, revision)
+
+            # Reset alembic.
+            alembic_api.stamp(self.config, None)
+
+            # We should only need the last few revisions.
+            with mock.patch.object(legacy_utils,
+                                   'is_migration_needed',
+                                   return_value=False):
+                for revision in revisions:
+                    LOG.info('Testing revision %s', revision)
+                    self._migrate_up(connection, revision)
+
+
+class TestMigrationsWalkSQLite(
+    DesignateMigrationsWalk,
+    test_fixtures.OpportunisticDBTestMixin,
+):
+    pass

test-requirements.txt

@@ -19,3 +19,4 @@ zake>=0.1.6 # Apache-2.0
 doc8>=0.6.0 # Apache-2.0
 Pygments>=2.2.0 # BSD license
 pymemcache!=1.3.0,>=1.2.9 # Apache 2.0 License
+PyMySQL>=0.8.0 # MIT License