Make sure to filter warnings to errors (#868)

Author: s-t-e-v-e-n-k

jenkinsapi_tests/unittests/test_build.py

@@ -277,6 +277,7 @@ def fake_get_data(cls, tree=None, params=None):
 
     with pytest.raises(Exception) as excinfo:
         with warnings.catch_warnings():
+            warnings.simplefilter("error")
             build.get_env_vars()
     assert "" == str(excinfo.value)