diff --git a/.circleci/run-tests.sh b/.circleci/run-tests.sh
index a97065ed9..d05719b32 100755
--- a/.circleci/run-tests.sh
+++ b/.circleci/run-tests.sh
@@ -31,7 +31,8 @@ JUNITXML="${ARTIFACTS}"/junit/unittests/results.xml
 sudo \
     SUBUNITREPORTER_OUTPUT_PATH="${SUBUNIT2}" \
     TAHOE_LAFS_TRIAL_ARGS="--reporter=subunitv2-file" \
-     --set-home \
+    PIP_NO_INDEX="1" \
+    --set-home \
      --user nobody \
      /tmp/tests/bin/tox \
      -c /tmp/project/tox.ini \