diff --git a/tools/docker/images/Dockerfile b/tools/docker/images/Dockerfile
index 3d1f3739..86f51795 100644
--- a/tools/docker/images/Dockerfile
+++ b/tools/docker/images/Dockerfile
@@ -1,6 +1,7 @@
 FROM opdavies/sculpin-serve AS app
 
 FROM app AS build
+ENV PATH=$PATH:/app/vendor/bin/phpunit
 WORKDIR /app
 COPY composer.* ./
 RUN composer install --no-dev