[httplib] provide a override context manager to switch the global tracer with a dummy one

Emanuele Palazzetti · Emanuele Palazzetti · commit 6a28ed22f82b · 2017-06-05T11:29:44.000-04:00
diff --git a/tests/contrib/httplib/test_httplib.py b/tests/contrib/httplib/test_httplib.py
@@ -11,8 +11,11 @@
 from ddtrace.contrib.httplib import patch, unpatch
 from ddtrace.contrib.httplib.patch import should_skip_request
 from ddtrace.pin import Pin
+
+from .utils import override_global_tracer
 from ...test_tracer import get_dummy_tracer
 
+
 if PY2:
     from urllib2 import urlopen, build_opener, Request
 else:
@@ -316,7 +319,9 @@ def test_urllib_request(self):
            we return the original response
            we capture a span for the request
         """
-        resp = urlopen('http://httpstat.us/200')
+        with override_global_tracer(self.tracer):
+            resp = urlopen('http://httpstat.us/200')
+
         self.assertEqual(self.to_str(resp.read()), '200 OK')
         self.assertEqual(resp.getcode(), 200)
 
@@ -338,7 +343,9 @@ def test_urllib_request_https(self):
                we return the original response
                we capture a span for the request
         """
-        resp = urlopen('https://httpbin.org/status/200')
+        with override_global_tracer(self.tracer):
+            resp = urlopen('https://httpbin.org/status/200')
+
         self.assertEqual(self.to_str(resp.read()), '')
         self.assertEqual(resp.getcode(), 200)
 
@@ -361,7 +368,9 @@ def test_urllib_request_object(self):
                we capture a span for the request
         """
         req = Request('http://httpstat.us/200')
-        resp = urlopen(req)
+        with override_global_tracer(self.tracer):
+            resp = urlopen(req)
+
         self.assertEqual(self.to_str(resp.read()), '200 OK')
         self.assertEqual(resp.getcode(), 200)
 
@@ -383,7 +392,9 @@ def test_urllib_request_opener(self):
            we capture a span for the request
         """
         opener = build_opener()
-        resp = opener.open('http://httpstat.us/200')
+        with override_global_tracer(self.tracer):
+            resp = opener.open('http://httpstat.us/200')
+
         self.assertEqual(self.to_str(resp.read()), '200 OK')
         self.assertEqual(resp.getcode(), 200)
 
@@ -410,7 +421,9 @@ def test_urllib_request(self):
                we return the original response
                we capture a span for the request
             """
-            resp = urllib.urlopen('http://httpstat.us/200')
+            with override_global_tracer(self.tracer):
+                resp = urllib.urlopen('http://httpstat.us/200')
+
             self.assertEqual(resp.read(), '200 OK')
             self.assertEqual(resp.getcode(), 200)
 
@@ -432,7 +445,9 @@ def test_urllib_request_https(self):
                    we return the original response
                    we capture a span for the request
             """
-            resp = urllib.urlopen('https://httpbin.org/status/200')
+            with override_global_tracer(self.tracer):
+                resp = urllib.urlopen('https://httpbin.org/status/200')
+
             self.assertEqual(resp.read(), '')
             self.assertEqual(resp.getcode(), 200)
 
diff --git a/tests/contrib/httplib/utils.py b/tests/contrib/httplib/utils.py
@@ -0,0 +1,16 @@
+import ddtrace
+
+from contextlib import contextmanager
+
+
+@contextmanager
+def override_global_tracer(tracer):
+    """Helper functions that overrides the global tracer available in the
+    `ddtrace` package. This is required because in some `httplib` tests we
+    can't get easily the PIN object attached to the `HTTPConnection` to
+    replace the used tracer with a dummy tracer.
+    """
+    original_tracer = ddtrace.tracer
+    ddtrace.tracer = tracer
+    yield
+    ddtrace.tracer = original_tracer
