CHANGE: return None from json if body is empty

tests/integration/aiohttp_utils.py

@@ -30,6 +30,14 @@ def aiohttp_app():
     async def hello(request):
         return aiohttp.web.Response(text='hello')
 
+    async def json(request):
+        return aiohttp.web.json_response({})
+
+    async def json_empty_body(request):
+        return aiohttp.web.json_response()
+
     app = aiohttp.web.Application()
     app.router.add_get('/', hello)
+    app.router.add_get('/json', json)
+    app.router.add_get('/json/empty', json_empty_body)
     return app

tests/integration/test_aiohttp.py

@@ -191,3 +191,26 @@ def test_aiohttp_test_client(aiohttp_client, tmpdir):
     response_text = loop.run_until_complete(response.text())
     assert response_text == 'hello'
     assert cassette.play_count == 1
+
+
+def test_aiohttp_test_client_json(aiohttp_client, tmpdir):
+    loop = asyncio.get_event_loop()
+    app = aiohttp_app()
+    url = '/json/empty'
+    client = loop.run_until_complete(aiohttp_client(app))
+
+    with vcr.use_cassette(str(tmpdir.join('get.yaml'))):
+        response = loop.run_until_complete(client.get(url))
+
+    assert response.status == 200
+    response_json = loop.run_until_complete(response.json())
+    assert response_json is None
+
+    with vcr.use_cassette(str(tmpdir.join('get.yaml'))) as cassette:
+        response = loop.run_until_complete(client.get(url))
+
+    request = cassette.requests[0]
+    assert request.url == str(client.make_url(url))
+    response_json = loop.run_until_complete(response.json())
+    assert response_json is None
+    assert cassette.play_count == 1

vcr/stubs/aiohttp_stubs/__init__.py

@@ -30,7 +30,11 @@ class MockClientResponse(ClientResponse):
         )
 
     async def json(self, *, encoding='utf-8', loads=json.loads, **kwargs):  # NOQA: E999
-        return loads(self._body.decode(encoding))
+        stripped = self._body.strip()
+        if not stripped:
+            return None
+
+        return loads(stripped.decode(encoding))
 
     async def text(self, encoding='utf-8', errors='strict'):
         return self._body.decode(encoding, errors=errors)