[Tests] ensure `doctoc` action fails when it should

.github/workflows/lint.yml

@@ -28,14 +28,10 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: ljharb/actions/node/run@main
-        name: 'npm install && npm run dockerfile_lint'
+        name: 'npm install && npm run doctoc'
         with:
           node-version: 'lts/*'
-          shell-command: |
+          command: "doctoc:check"
-            set -e
-            cp README.md README.md.orig
-            npm run doctoc
-            diff -q README.md README.md.orig
 
   test_naming:
     runs-on: ubuntu-latest

package.json

@@ -15,6 +15,9 @@
     "test/installation/iojs": "shell=$(basename -- $(ps -o comm= $(ps -o ppid= -p $PPID)) | sed 's/^-//'); make TEST_SUITE=installation_iojs test-$shell",
     "test/sourcing": "shell=$(basename -- $(ps -o comm= $(ps -o ppid= -p $PPID)) | sed 's/^-//'); make TEST_SUITE=sourcing test-$shell",
     "doctoc": "doctoc --title='## Table of Contents' --github README.md",
+    "predoctoc:check": "cp README.md v-README.md.orig && npm run doctoc",
+    "doctoc:check": "diff -q README.md v-README.md.orig",
+    "postdoctoc:check": "mv v-README.md.orig README.md",
     "eclint": "eclint check $(git ls-tree --name-only HEAD | xargs)",
     "dockerfile_lint": "dockerfile_lint"
   },