temporarily pin pytest to avoid test bug
diff --git a/tox.ini b/tox.ini
index 4c8ac4c..6e68b0e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,7 +8,7 @@
 passenv = LANG
 usedevelop = true
 deps =
-    pytest>=3
+    pytest>=3,<3.7
     coverage
 
 commands = coverage run -p -m pytest {posargs}