diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6dcb758..2afce81 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -42,6 +42,7 @@ jobs:
           - 3.2
           - 3.3
           - 3.4
+          - "4.0"
           - jruby
 
     runs-on: ubuntu-latest