diff --git a/.github/workflows/run-tests.yaml b/.github/workflows/run-tests.yaml
index 1d7be97..a885d34 100644
--- a/.github/workflows/run-tests.yaml
+++ b/.github/workflows/run-tests.yaml
@@ -6,7 +6,7 @@ on: [push, pull_request]
 jobs:
   test:
     name: Mininet-tests
-    runs-on: ubuntu-18.04 ubuntu 16.04
+    runs-on: ubuntu-18.04 ubuntu-16.04
     steps:
       - name: Checking out Mininet source
         uses: actions/checkout@v2