test(request_id): add tests for request id middleware context handling

Add tests to verify that request_id is unique per request and correctly set in response headers. Tests include checks for isolation in async calls and persistence in synchronous requests.

Related to issue falconry#2260

examples/recipes/request_id_middleware.py

@@ -1,13 +1,15 @@
 # middleware.py
 
 from uuid import uuid4
+
 from .request_id_context import ctx
 
+
 class RequestIDMiddleware:
     def process_request(self, req, resp):
         request_id = str(uuid4())
-        ctx.request_id = request_id  
-        req.context.request_id = request_id  
+        ctx.request_id = request_id
+        req.context.request_id = request_id
 
     # It may also be helpful to include the ID in the response
     def process_response(self, req, resp, resource, req_succeeded):

tests/test_recipes.py

@@ -1,10 +1,11 @@
+import asyncio
+
 import pytest
 
+from examples.recipes.request_id_middleware import RequestIDMiddleware
 import falcon
 import falcon.testing
-import asyncio
 
-from examples.recipes.request_id_middleware import RequestIDMiddleware
 
 class TestMultipartMixed:
     """Test parsing example from the now-obsolete RFC 1867:
@@ -143,7 +144,8 @@ def test_raw_path(self, asgi, app_kind, util):
         )
         assert result2.status_code == 200
         assert result2.json == {'cached': True}
-
+
+
 class TestRequestIDContext:
     @pytest.fixture
     def app(self):
@@ -162,15 +164,17 @@ async def make_request():
             return response.json['request_id']
 
         loop = asyncio.get_event_loop()
-        request_id1, request_id2 = loop.run_until_complete(asyncio.gather(make_request(), make_request()))
+        request_id1, request_id2 = loop.run_until_complete(
+            asyncio.gather(make_request(), make_request())
+        )
         assert request_id1 != request_id2
 
     def test_request_id_persistence(self, app):
         client = falcon.testing.TestClient(app)
-        
+
         response = client.simulate_get('/test')
         request_id1 = response.json['request_id']
-        
+
         response = client.simulate_get('/test')
         request_id2 = response.json['request_id']
 
@@ -181,4 +185,4 @@ def test_request_id_in_response_header(self, app):
 
         response = client.simulate_get('/test')
         assert 'X-Request-ID' in response.headers
-        assert response.headers['X-Request-ID'] == response.json['request_id']
+        assert response.headers['X-Request-ID'] == response.json['request_id']