Don't try to mock context manager; use a simple class instead

.github/workflows/ci.yaml

@@ -63,7 +63,7 @@ jobs:
         run: psql --echo-errors --quiet -c '\timing off' -c "CREATE DATABASE ${TEST_DATABASE_NAME};" ${ADMIN_DATABASE_URL}
 
       - name: river migrate-up
-        run: river migrate-up --database-url "$TEST_DATABASE_URL"
+        run: river migrate-up --database-url "$TEST_DATABASE_URL" --max-steps 5 # temporarily include max steps so tests can pass with unique fixes
 
       - name: Test
         run: rye test
@@ -109,7 +109,7 @@ jobs:
         run: psql --echo-errors --quiet -c '\timing off' -c "CREATE DATABASE ${DATABASE_NAME};" ${ADMIN_DATABASE_URL}
 
       - name: river migrate-up
-        run: river migrate-up --database-url "$DATABASE_URL"
+        run: river migrate-up --database-url "$DATABASE_URL" --max-steps 5 # temporarily include max steps so tests can pass with unique fixes
 
       - name: Run examples
         run: rye run python3 -m examples.all

tests/client_test.py

@@ -1,6 +1,6 @@
 from dataclasses import dataclass
 from datetime import datetime, timezone
-from unittest.mock import MagicMock, Mock, patch
+from unittest.mock import MagicMock, patch
 
 import pytest
 
@@ -16,17 +16,20 @@ def mock_driver() -> DriverProtocol:
 
 @pytest.fixture
 def mock_exec(mock_driver) -> ExecutorProtocol:
-    def mock_context_manager(val) -> Mock:
-        context_manager_mock = MagicMock()
-        context_manager_mock.__enter__.return_value = val
-        context_manager_mock.__exit__.return_value = Mock()
-        return context_manager_mock
+    # Don't try to mock a context manager. It will cause endless pain around the
+    # edges like swallowing raised exceptions.
+    class TrivialContextManager:
+        def __init__(self, with_val):
+            self.with_val = with_val
 
-    # def mock_context_manager(val) -> Mock:
-    #     return Mock(__enter__=val, __exit__=Mock())
+        def __enter__(self):
+            return self.with_val
+
+        def __exit__(self, exc_type, exc_val, exc_tb):
+            pass
 
     mock_exec = MagicMock(spec=ExecutorProtocol)
-    mock_driver.executor.return_value = mock_context_manager(mock_exec)
+    mock_driver.executor.return_value = TrivialContextManager(mock_exec)
 
     return mock_exec