add test for spans

Author: lannuttia

instrumentation/opentelemetry-instrumentation-fastapi/tests/test_fastapi_instrumentation.py

@@ -20,7 +20,7 @@
 import weakref as _weakref
 from contextlib import ExitStack
 from timeit import default_timer
-from typing import Any, cast
+from typing import Any, Final, cast
 from unittest.mock import Mock, call, patch
 
 import fastapi
@@ -341,15 +341,29 @@ def test_sub_app_fastapi_call(self):
             span.attributes[HTTP_URL],
         )
 
-
     def test_custom_api_router(self):
         """
         This test is to ensure that custom API routers the OpenTelemetryMiddleware does not cause issues with
         custom API routers that depend on non-standard fields on the ASGI scope.
         """
-        resp = self._client.get("/custom-router/success")
-        self.assertEqual(resp.status_code, 200)
-
+        resp: Final = self._client.get("/custom-router/success")
+        spans: Final = self.memory_exporter.get_finished_spans()
+        expected_span_attributes: Final = {
+            HTTP_TARGET: "/custom-router/success",
+            HTTP_URL: "https://testserver/",
+        }
+        self.assertEqual(200, resp.status_code)
+        self.assertTrue(
+            all(
+                all(
+                    (
+                        span.attributes[attribute] == expected
+                        for attribute, expected in expected_span_attributes.items()
+                    )
+                )
+                for span in spans
+            )
+        )
 
     def test_host_fastapi_call(self):
         client = TestClient(self._app, base_url="https://testserver2:443")