Fixes error on Travis build for Python 3.2

sdispater · sdispater · commit fe199c75a466 · 2016-09-05T18:01:50.000-05:00
diff --git a/tests-requirements.txt b/tests-requirements.txt
@@ -1,3 +1,4 @@
 -r requirements.txt
 pytest
 pytest-cov
+coverage<4
