Add check formatting step to test.yml

Author: BSKY

.github/workflows/test.yml

@@ -1,25 +1,40 @@
 name: Test ocaml-action
 
 on:
-  push:
-    branches:
-      - "master"
-      - "releases/*"
-  pull_request:
+  - push
+  - pull_request
 
 jobs:
   test:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
-        ocaml-version: ["4.08.1", "4.05.0"]
+        os:
+          - macos-latest
+          - ubuntu-latest
+          - windows-latest
+        node-version:
+          - 13.x
+        ocaml-version:
+          - 4.08.1
+          - 4.05.0
 
     runs-on: ${{ matrix.os }}
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/[email protected]
+
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/[email protected]
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Install npm packages
+        run: yarn --frozen-lockfile
+
+      - name: Check formatting
+        run: yarn fmt:check
 
       - name: Use OCaml ${{ matrix.ocaml-version }}
         uses: ./