diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 9b16787..b8e60fa 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -1,6 +1,6 @@
 name: CI
 
-on: [push,pull_request]
+on: [push, pull_request]
 
 jobs:
   build:
@@ -12,6 +12,13 @@ jobs:
         exclude:
           - os: windows-latest
             ruby: head
+          - { os: macos-latest, ruby: '2.3' }
+          - { os: macos-latest, ruby: '2.4' }
+          - { os: macos-latest, ruby: '2.5' }
+        include:
+          - { os: macos-13, ruby: '2.3' }
+          - { os: macos-13, ruby: '2.4' }
+          - { os: macos-13, ruby: '2.5' }
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v2