diff --git a/run-unit-test-docker.sh b/run-unit-test-docker.sh
index b3ecde9..9c7bc49 100755
--- a/run-unit-test-docker.sh
+++ b/run-unit-test-docker.sh
@@ -78,7 +78,8 @@
 echo "Building docker image with build-unit-test-docker"
 # Export input env variables
 export BRANCH
-export DOCKER_IMG_NAME=$(./scripts/build-unit-test-docker)
+DOCKER_IMG_NAME=$(./scripts/build-unit-test-docker)
+export DOCKER_IMG_NAME
 
 # Allow the user to pass options through to unit-test.py:
 #   EXTRA_UNIT_TEST_ARGS="-r 100" ...