Use HTTP mock server for tornado tests

Fixes open-telemetry#1681

instrumentation/opentelemetry-instrumentation-tornado/pyproject.toml

@@ -37,6 +37,7 @@ instruments = [
 test = [
   "opentelemetry-instrumentation-tornado[instruments]",
   "opentelemetry-test-utils == 0.40b0.dev",
+  "http-server-mock"
 ]
 
 [project.entry-points.opentelemetry_instrumentor]

instrumentation/opentelemetry-instrumentation-tornado/tests/test_instrumentation.py

@@ -15,6 +15,7 @@
 
 from unittest.mock import Mock, patch
 
+from http_server_mock import HttpServerMock
 from tornado.testing import AsyncHTTPTestCase
 
 from opentelemetry import trace
@@ -494,32 +495,35 @@ def test_response_headers(self):
         self.memory_exporter.clear()
         set_global_response_propagator(orig)
 
-    # todo(srikanthccv): fix this test
-    # this test is making request to real httpbin.org/status/200 which
-    # is not a good idea as it can fail due to availability of the
-    # service.
-    # def test_credential_removal(self):
-    #     response = self.fetch(
-    #         "http://username:[email protected]/status/200"
-    #     )
-    #     self.assertEqual(response.code, 200)
-
-    #     spans = self.sorted_spans(self.memory_exporter.get_finished_spans())
-    #     self.assertEqual(len(spans), 1)
-    #     client = spans[0]
-
-    #     self.assertEqual(client.name, "GET")
-    #     self.assertEqual(client.kind, SpanKind.CLIENT)
-    #     self.assertSpanHasAttributes(
-    #         client,
-    #         {
-    #             SpanAttributes.HTTP_URL: "http://httpbin.org/status/200",
-    #             SpanAttributes.HTTP_METHOD: "GET",
-    #             SpanAttributes.HTTP_STATUS_CODE: 200,
-    #         },
-    #     )
-
-    #     self.memory_exporter.clear()
+    def test_credential_removal(self):
+        app = HttpServerMock("test_credential_removal")
+
+        @app.route("/status/200")
+        def index():
+            return "hello"
+
+        with app.run("localhost", 5000):
+            response = self.fetch(
+                "http://username:password@localhost:5000/status/200"
+            )
+        self.assertEqual(response.code, 200)
+
+        spans = self.sorted_spans(self.memory_exporter.get_finished_spans())
+        self.assertEqual(len(spans), 1)
+        client = spans[0]
+
+        self.assertEqual(client.name, "GET")
+        self.assertEqual(client.kind, SpanKind.CLIENT)
+        self.assertSpanHasAttributes(
+            client,
+            {
+                SpanAttributes.HTTP_URL: "http://localhost:5000/status/200",
+                SpanAttributes.HTTP_METHOD: "GET",
+                SpanAttributes.HTTP_STATUS_CODE: 200,
+            },
+        )
+
+        self.memory_exporter.clear()
 
 
 class TestTornadoInstrumentationWithXHeaders(TornadoTest):