[ci] add integration tests for the downgrade behavior

Author: Emanuele Palazzetti

ddtrace/encoding.py

@@ -1,4 +1,3 @@
-import os
 import json
 import logging
 

tests/test_integration.py

@@ -10,7 +10,7 @@
 from ddtrace.api import API
 from ddtrace.span import Span
 from ddtrace.tracer import Tracer
-from ddtrace.encoding import JSONEncoder, MsgpackEncoder
+from ddtrace.encoding import JSONEncoder, MsgpackEncoder, get_encoder
 from tests.test_tracer import get_dummy_tracer
 
 
@@ -278,3 +278,44 @@ def test_send_service_called_multiple_times(self):
         response = self.api_msgpack.send_services(services)
         ok_(response)
         eq_(response.status, 200)
+
+@skipUnless(
+    os.environ.get('TEST_DATADOG_INTEGRATION', False),
+    'You should have a running trace agent and set TEST_DATADOG_INTEGRATION=1 env variable'
+)
+class TestAPIDowngrade(TestCase):
+    """
+    Ensures that if the tracing client found an earlier trace agent,
+    it will downgrade the current connection to a stable API version
+    """
+    def test_get_encoder_default(self):
+        # get_encoder should return MsgpackEncoder instance if
+        # msgpack and the CPP implementaiton are available
+        encoder = get_encoder()
+        ok_(isinstance(encoder, MsgpackEncoder))
+
+    @mock.patch('ddtrace.encoding.MSGPACK_ENCODING', False)
+    def test_get_encoder_fallback(self):
+        # get_encoder should return JSONEncoder instance if
+        # msgpack or the CPP implementaiton, are not available
+        encoder = get_encoder()
+        ok_(isinstance(encoder, JSONEncoder))
+
+    def test_downgrade_api(self):
+        # make a call to a not existing endpoint, downgrades
+        # the current API to a stable one
+        tracer = get_dummy_tracer()
+        tracer.trace('client.testing').finish()
+        trace = tracer.writer.pop()
+
+        # the encoder is right but we're targeting an API
+        # endpoint that is not available
+        api = API('localhost', 7777)
+        api._traces = '/v0.0/traces'
+        ok_(isinstance(api._encoder, MsgpackEncoder))
+
+        # after the call, we downgrade to a working endpoint
+        response = api.send_traces([trace])
+        ok_(response)
+        eq_(response.status, 200)
+        ok_(isinstance(api._encoder, JSONEncoder))

tox.ini

@@ -11,6 +11,7 @@ envlist =
     wait
 
     {py27,py34}-tracer
+    {py27,py34}-integration
     {py27,py34}-contrib
     {py27,py34}-bottle{12}-webtest
     {py27,py34}-cassandra
@@ -38,7 +39,7 @@ deps =
 # test dependencies installed in all envs
     mock
     nose
-    msgpack-python<0.4.9
+    msgpack-python
 # integrations
     contrib: blinker
     contrib: bottle
@@ -101,7 +102,9 @@ commands =
 # wait for services script
     {py34}-wait: python tests/wait-for-services.py
 # run only essential tests related to the tracing client
-    {py27,py34}-tracer: nosetests {posargs} --exclude=".*(contrib).*" tests/
+    {py27,py34}-tracer: nosetests {posargs} --exclude=".*(contrib|integration).*" tests/
+# integration tests
+    {py27,py34}-integration: nosetests {posargs} tests/test_integration.py
 # run all tests for the release jobs except the ones with a different test runner
     {py27,py34}-contrib: nosetests {posargs} --exclude=".*(django).*" tests/contrib/
 # run subsets of the tests for particular library versions
@@ -141,5 +144,5 @@ basepython=python
 
 [flake8]
 ignore=W391,E231,E201,E202,E203,E261,E302,E128,E126,E124
-max-line-length=100
+max-line-length=120
 exclude = tests