Add tests for debugger middleware

tests/test_middleware_debugger_class.py

@@ -0,0 +1,53 @@
+from unittest.mock import MagicMock, patch
+
+import pytest
+from fastapi import FastAPI
+from fastapi.middleware.debugger import (
+    DebuggerMiddleware,
+    webpdb_catch_exceptions_middleware,
+)
+from fastapi.testclient import TestClient
+
+MAGIC_VALUE_THAT_NEVER_RETURNS = 42
+
+
+def get_client_for_new_app(middlware_params=None):
+    app = FastAPI()
+    app.add_middleware(DebuggerMiddleware, **(middlware_params or {}))
+
+    @app.get("/call-debugger-on-raise")
+    async def raise_exception():
+        raise ValueError("Test")
+        return MAGIC_VALUE_THAT_NEVER_RETURNS
+
+    return TestClient(app)
+
+
+@pytest.fixture
+def pdb_test_client():
+    return get_client_for_new_app()
+
+
+@pytest.fixture
+def webpdb_test_client():
+    return get_client_for_new_app(
+        {"start_debugger_func": webpdb_catch_exceptions_middleware}
+    )
+
+
+def test_pdb(pdb_test_client):
+    pdb_mock = MagicMock()
+    with patch.dict("sys.modules", {"pdb": pdb_mock}):
+        with pytest.raises(ValueError):
+            _ = pdb_test_client.get("/call-debugger-on-raise")
+
+    assert pdb_mock.pm.called
+
+
+def test_webpdb(webpdb_test_client):
+    webpdb_mock = MagicMock()
+    with patch.dict("sys.modules", {"web_pdb": webpdb_mock}):
+        with pytest.raises(ValueError):
+            _ = webpdb_test_client.get("/call-debugger-on-raise")
+
+    assert webpdb_mock.catch_post_mortem.called