Add tests for subclassed clients

Author: xrmx

instrumentation/opentelemetry-instrumentation-httpx/tests/test_httpx_integration.py

@@ -1183,6 +1183,21 @@ def perform_request(
     def create_proxy_transport(self, url):
         return httpx.HTTPTransport(proxy=httpx.Proxy(url))
 
+    def test_can_instrument_subclassed_client(self):
+        class CustomClient(httpx.Client):
+            pass
+
+        client = CustomClient()
+        self.assertFalse(
+            isinstance(client._transport.handle_request, ObjectProxy)
+        )
+
+        HTTPXClientInstrumentor().instrument()
+
+        self.assertTrue(
+            isinstance(client._transport.handle_request, ObjectProxy)
+        )
+
 
 class TestAsyncInstrumentationIntegration(BaseTestCases.BaseInstrumentorTest):
     response_hook = staticmethod(_async_response_hook)
@@ -1258,3 +1273,18 @@ def test_async_request_hook_does_nothing_if_not_coroutine(self):
         self.assertEqual(result.text, "Hello!")
         span = self.assert_span()
         self.assertEqual(span.name, "GET")
+
+    def test_can_instrument_subclassed_async_client(self):
+        class CustomAsyncClient(httpx.AsyncClient):
+            pass
+
+        client = CustomAsyncClient()
+        self.assertFalse(
+            isinstance(client._transport.handle_async_request, ObjectProxy)
+        )
+
+        HTTPXClientInstrumentor().instrument()
+
+        self.assertTrue(
+            isinstance(client._transport.handle_async_request, ObjectProxy)
+        )