add handler with response body to unit tests

Author: weizhikuan

instrumentation/opentelemetry-instrumentation-aiohttp-client/tests/test_aiohttp_client_integration.py

@@ -1285,6 +1285,10 @@ def tearDown(self):
     async def default_handler(request):
         return aiohttp.web.Response(status=int(200))
 
+    @staticmethod
+    async def handler_with_body(request):
+        return aiohttp.web.Response(status=200, body=b"hello")
+
     @staticmethod
     def get_default_request(url: str = URL):
         async def default_request(server: aiohttp.test_utils.TestServer):
@@ -1627,7 +1631,7 @@ def test_response_body_size_not_set_by_default(self):
         AioHttpClientInstrumentor().instrument()
 
         run_with_test_server(
-            self.get_default_request(), self.URL, self.default_handler
+            self.get_default_request(), self.URL, self.handler_with_body
         )
         span = self._assert_spans(1)
         self.assertNotIn(HTTP_RESPONSE_BODY_SIZE, span.attributes)
@@ -1643,7 +1647,7 @@ def test_response_body_size_set_on_span(self):
         AioHttpClientInstrumentor().uninstrument()
         AioHttpClientInstrumentor().instrument()
         run_with_test_server(
-            self.get_default_request(), self.URL, self.default_handler
+            self.get_default_request(), self.URL, self.handler_with_body
         )
         span = self._assert_spans(1)
         self.assertIn(HTTP_RESPONSE_BODY_SIZE, span.attributes)
@@ -1659,8 +1663,9 @@ def test_response_body_size_set_on_span(self):
     def test_response_body_size_metric_recorded(self):
         AioHttpClientInstrumentor().uninstrument()
         AioHttpClientInstrumentor().instrument()
+
         run_with_test_server(
-            self.get_default_request(), self.URL, self.default_handler
+            self.get_default_request(), self.URL, self.handler_with_body
         )
         metrics = self._assert_metrics(2)
         metric_names = {m.name for m in metrics}
@@ -1682,7 +1687,7 @@ def test_response_body_size_not_set_without_new_semconv(self):
         AioHttpClientInstrumentor().uninstrument()
         AioHttpClientInstrumentor().instrument()
         run_with_test_server(
-            self.get_default_request(), self.URL, self.default_handler
+            self.get_default_request(), self.URL, self.handler_with_body
         )
         span = self._assert_spans(1)
         self.assertNotIn(HTTP_RESPONSE_BODY_SIZE, span.attributes)