oslo.db/oslo_db/tests/old_import_api/sqlalchemy/test_handle_error.py

#    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.

"""Test the compatibility layer for the handle_error() event.

This event is added as of SQLAlchemy 0.9.7; oslo.db provides a compatibility
layer for prior SQLAlchemy versions.

"""

import mock
from oslotest import base as test_base
import sqlalchemy as sqla
from sqlalchemy.sql import column
from sqlalchemy.sql import literal
from sqlalchemy.sql import select
from sqlalchemy.types import Integer
from sqlalchemy.types import TypeDecorator

from oslo.db.sqlalchemy import compat
from oslo.db.sqlalchemy.compat import utils
from oslo_db.tests.old_import_api import utils as test_utils


class MyException(Exception):
    pass


class ExceptionReraiseTest(test_base.BaseTestCase):

    def setUp(self):
        super(ExceptionReraiseTest, self).setUp()

        self.engine = engine = sqla.create_engine("sqlite://")
        self.addCleanup(engine.dispose)

    def _fixture(self):
        engine = self.engine

        def err(context):
            if "ERROR ONE" in str(context.statement):
                raise MyException("my exception")
        compat.handle_error(engine, err)

    def test_exception_event_altered(self):
        self._fixture()

        with mock.patch.object(self.engine.dialect.execution_ctx_cls,
                               "handle_dbapi_exception") as patched:

            matchee = self.assertRaises(
                MyException,
                self.engine.execute, "SELECT 'ERROR ONE' FROM I_DONT_EXIST"
            )
            self.assertEqual(1, patched.call_count)
            self.assertEqual("my exception", matchee.args[0])

    def test_exception_event_non_altered(self):
        self._fixture()

        with mock.patch.object(self.engine.dialect.execution_ctx_cls,
                               "handle_dbapi_exception") as patched:

            self.assertRaises(
                sqla.exc.DBAPIError,
                self.engine.execute, "SELECT 'ERROR TWO' FROM I_DONT_EXIST"
            )
            self.assertEqual(1, patched.call_count)

    def test_is_disconnect_not_interrupted(self):
        self._fixture()

        with test_utils.nested(
            mock.patch.object(
                self.engine.dialect.execution_ctx_cls,
                "handle_dbapi_exception"
            ),
            mock.patch.object(
                self.engine.dialect, "is_disconnect",
                lambda *args: True
            )
        ) as (handle_dbapi_exception, is_disconnect):
            with self.engine.connect() as conn:
                self.assertRaises(
                    MyException,
                    conn.execute, "SELECT 'ERROR ONE' FROM I_DONT_EXIST"
                )
                self.assertEqual(1, handle_dbapi_exception.call_count)
                self.assertTrue(conn.invalidated)

    def test_no_is_disconnect_not_invalidated(self):
        self._fixture()

        with test_utils.nested(
            mock.patch.object(
                self.engine.dialect.execution_ctx_cls,
                "handle_dbapi_exception"
            ),
            mock.patch.object(
                self.engine.dialect, "is_disconnect",
                lambda *args: False
            )
        ) as (handle_dbapi_exception, is_disconnect):
            with self.engine.connect() as conn:
                self.assertRaises(
                    MyException,
                    conn.execute, "SELECT 'ERROR ONE' FROM I_DONT_EXIST"
                )
                self.assertEqual(1, handle_dbapi_exception.call_count)
                self.assertFalse(conn.invalidated)

    def test_exception_event_ad_hoc_context(self):
        engine = self.engine

        nope = MyException("nope")

        class MyType(TypeDecorator):
            impl = Integer

            def process_bind_param(self, value, dialect):
                raise nope

        listener = mock.Mock(return_value=None)
        compat.handle_error(engine, listener)

        self.assertRaises(
            sqla.exc.StatementError,
            engine.execute,
            select([1]).where(column('foo') == literal('bar', MyType))
        )

        ctx = listener.mock_calls[0][1][0]
        self.assertTrue(ctx.statement.startswith("SELECT 1 "))
        self.assertIs(ctx.is_disconnect, False)
        self.assertIs(ctx.original_exception, nope)

    def _test_alter_disconnect(self, orig_error, evt_value):
        engine = self.engine

        def evt(ctx):
            ctx.is_disconnect = evt_value
        compat.handle_error(engine, evt)

        # if we are under sqla 0.9.7, and we are expecting to take
        # an "is disconnect" exception and make it not a disconnect,
        # that isn't supported b.c. the wrapped handler has already
        # done the invalidation.
        expect_failure = not utils.sqla_097 and orig_error and not evt_value

        with mock.patch.object(engine.dialect,
                               "is_disconnect",
                               mock.Mock(return_value=orig_error)):

            with engine.connect() as c:
                conn_rec = c.connection._connection_record
                try:
                    c.execute("SELECT x FROM nonexistent")
                    assert False
                except sqla.exc.StatementError as st:
                    self.assertFalse(expect_failure)

                    # check the exception's invalidation flag
                    self.assertEqual(st.connection_invalidated, evt_value)

                    # check the Connection object's invalidation flag
                    self.assertEqual(c.invalidated, evt_value)

                    # this is the ConnectionRecord object; it's invalidated
                    # when its .connection member is None
                    self.assertEqual(conn_rec.connection is None, evt_value)

                except NotImplementedError as ne:
                    self.assertTrue(expect_failure)
                    self.assertEqual(
                        str(ne),
                        "Can't reset 'disconnect' status of exception once it "
                        "is set with this version of SQLAlchemy")

    def test_alter_disconnect_to_true(self):
        self._test_alter_disconnect(False, True)
        self._test_alter_disconnect(True, True)

    def test_alter_disconnect_to_false(self):
        self._test_alter_disconnect(True, False)
        self._test_alter_disconnect(False, False)