add libuv to the test matrix. fix prospector.

.travis.yml

@@ -9,6 +9,7 @@ env:
     matrix:
       # These are ordered to get as much diversity in the
       # first group of parallel runs (4) as posible
+      - TASK=test-py27-libuv
       - TASK=test-py27-noembed
       - TASK=test-pypy
       - TASK=test-py36

Makefile

@@ -186,6 +186,9 @@ test-pypy3: $(PYPY3)
 test-py27-cffi: $(PY27)
 	GEVENT_CORE_CFFI_ONLY=1 PYTHON=python2.7 PATH=$(BUILD_RUNTIMES)/versions/python2.7/bin:$(PATH) make develop toxtest
 
+test-py27-libuv: $(PY27)
+	GEVENT_CORE_CFFI_ONLY=libuv PYTHON=python2.7 PATH=$(BUILD_RUNTIMES)/versions/python2.7/bin:$(PATH) make develop toxtest
+
 test-py27-noembed: $(PY27)
 	cd deps/libev && ./configure --disable-dependency-tracking && make
 	cd deps/c-ares && ./configure --disable-dependency-tracking && make

src/gevent/libuv/loop.py

@@ -5,7 +5,6 @@ libuv loop implementation
 from __future__ import absolute_import, print_function
 
 import os
-import sys
 from collections import defaultdict
 from collections import namedtuple
 import signal

src/gevent/os.py

@@ -277,6 +277,7 @@ if hasattr(os, 'fork'):
             .. versionchanged:: 1.2a1
                More cases are handled in a cooperative manner.
             """
+            # pylint: disable=too-many-return-statements
             # XXX Does not handle tracing children
 
             # So long as libev's loop doesn't run, it's OK to add

tox.ini

 [tox]
 envlist =
-    py27,py33,py34,py35,py36,py27-cffi,pypy,pypy3,lint
+    py27,py33,py34,py35,py36,py27-cffi,py27-libuv,pypy,lint
 
 [testenv]
 deps =
@@ -48,6 +48,15 @@ setenv =
 commands =
     make toxtest
 
+[testenv:py27-libuv]
+basepython =
+    python2.7
+setenv =
+	GEVENT_CORE_CFFI_ONLY=libuv
+commands =
+    make toxtest
+
+
 [testenv:leak]
 basepython =
     python2.7