diff --git a/integration/util.py b/integration/util.py
index bbcf5efc6..a64bcbf8e 100644
--- a/integration/util.py
+++ b/integration/util.py
@@ -1,7 +1,7 @@
 import sys
 import time
 import json
-from os import mkdir
+from os import mkdir, environ
 from os.path import exists, join
 from six.moves import StringIO
 from functools import partial
@@ -145,6 +145,7 @@ def _tahoe_runner_optional_coverage(proto, reactor, request, other_args):
         proto,
         sys.executable,
         args,
+        env=environ,
     )