diff options
| -rw-r--r-- | changelog.d/12198.misc | 1 | ||||
| -rw-r--r-- | tests/storage/test_database.py | 104 |
2 files changed, 104 insertions, 1 deletions
diff --git a/changelog.d/12198.misc b/changelog.d/12198.misc new file mode 100644 index 0000000000..6b184a9053 --- /dev/null +++ b/changelog.d/12198.misc @@ -0,0 +1 @@ +Add tests for database transaction callbacks. diff --git a/tests/storage/test_database.py b/tests/storage/test_database.py index 8597867563..ae13bed086 100644 --- a/tests/storage/test_database.py +++ b/tests/storage/test_database.py @@ -12,7 +12,18 @@ # See the License for the specific language governing permissions and # limitations under the License. -from synapse.storage.database import make_tuple_comparison_clause +from typing import Callable, Tuple +from unittest.mock import Mock, call + +from twisted.test.proto_helpers import MemoryReactor + +from synapse.server import HomeServer +from synapse.storage.database import ( + DatabasePool, + LoggingTransaction, + make_tuple_comparison_clause, +) +from synapse.util import Clock from tests import unittest @@ -22,3 +33,94 @@ class TupleComparisonClauseTestCase(unittest.TestCase): clause, args = make_tuple_comparison_clause([("a", 1), ("b", 2)]) self.assertEqual(clause, "(a,b) > (?,?)") self.assertEqual(args, [1, 2]) + + +class CallbacksTestCase(unittest.HomeserverTestCase): + """Tests for transaction callbacks.""" + + def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None: + self.store = hs.get_datastores().main + self.db_pool: DatabasePool = self.store.db_pool + + def _run_interaction( + self, func: Callable[[LoggingTransaction], object] + ) -> Tuple[Mock, Mock]: + """Run the given function in a database transaction, with callbacks registered. + + Args: + func: The function to be run in a transaction. The transaction will be + retried if `func` raises an `OperationalError`. + + Returns: + Two mocks, which were registered as an `after_callback` and an + `exception_callback` respectively, on every transaction attempt. + """ + after_callback = Mock() + exception_callback = Mock() + + def _test_txn(txn: LoggingTransaction) -> None: + txn.call_after(after_callback, 123, 456, extra=789) + txn.call_on_exception(exception_callback, 987, 654, extra=321) + func(txn) + + try: + self.get_success_or_raise( + self.db_pool.runInteraction("test_transaction", _test_txn) + ) + except Exception: + pass + + return after_callback, exception_callback + + def test_after_callback(self) -> None: + """Test that the after callback is called when a transaction succeeds.""" + after_callback, exception_callback = self._run_interaction(lambda txn: None) + + after_callback.assert_called_once_with(123, 456, extra=789) + exception_callback.assert_not_called() + + def test_exception_callback(self) -> None: + """Test that the exception callback is called when a transaction fails.""" + _test_txn = Mock(side_effect=ZeroDivisionError) + after_callback, exception_callback = self._run_interaction(_test_txn) + + after_callback.assert_not_called() + exception_callback.assert_called_once_with(987, 654, extra=321) + + def test_failed_retry(self) -> None: + """Test that the exception callback is called for every failed attempt.""" + # Always raise an `OperationalError`. + _test_txn = Mock(side_effect=self.db_pool.engine.module.OperationalError) + after_callback, exception_callback = self._run_interaction(_test_txn) + + after_callback.assert_not_called() + exception_callback.assert_has_calls( + [ + call(987, 654, extra=321), + call(987, 654, extra=321), + call(987, 654, extra=321), + call(987, 654, extra=321), + call(987, 654, extra=321), + call(987, 654, extra=321), + ] + ) + self.assertEqual(exception_callback.call_count, 6) # no additional calls + + def test_successful_retry(self) -> None: + """Test callbacks for a failed transaction followed by a successful attempt.""" + # Raise an `OperationalError` on the first attempt only. + _test_txn = Mock( + side_effect=[self.db_pool.engine.module.OperationalError, None] + ) + after_callback, exception_callback = self._run_interaction(_test_txn) + + # Calling both `after_callback`s when the first attempt failed is rather + # surprising (#12184). Let's document the behaviour in a test. + after_callback.assert_has_calls( + [ + call(123, 456, extra=789), + call(123, 456, extra=789), + ] + ) + self.assertEqual(after_callback.call_count, 2) # no additional calls + exception_callback.assert_not_called() |