diff --git a/Dockerfile b/Dockerfile
index 3c9c8efa..91e2971d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,4 +6,4 @@ WORKDIR /app
 
 RUN pip install --no-cache-dir -r requirements.txt
 
-CMD ["pytest", "--network=$NETWORK", "test_v4_router.py"]
+CMD ["pytest", "--network", $NETWORK, "test_v4_router.py"]