diff --git a/tox.ini b/tox.ini
index fbd2a40..7706b18 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,9 +4,9 @@ skip_missing_interpreters = True
 
 [testenv]
 commands =
-    coverage erase
     coverage run test_contextlib2.py
     coverage report
+    coverage combine
     coverage xml
 deps =
     coverage