add PR check of node modules

.github/workflows/pr-checks.yml

@@ -1,4 +1,4 @@
-name: "Lint, Build & Test"
+name: "PR checks"
 
 on: [push, pull_request]
 
@@ -30,10 +30,38 @@ jobs:
         if [ ! -z "$(git status --porcelain)" ]; then
           # If we get a fail here then the PR needs attention
           >&2 echo "Failed: JavaScript files are not up to date. Run 'npm run-script build' to update"
+          git status
           exit 1
         fi
         echo "Success: JavaScript files are up to date"
 
+  check-node-modules:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Check node modules up to date
+      run: |
+        # Sanity check that repo is clean to start with
+        if [ ! -z "$(git status --porcelain)" ]; then
+          # If we get a fail here then this workflow needs attention...
+          >&2 echo "Failed: Repo should be clean before testing!"
+          exit 1
+        fi
+
+        # Reinstall modules and then clean to remove absolute paths
+        # Use 'npm ci' instead of 'npm install' as this is intended to be reproducible
+        npm ci
+        npm run removeNPMAbsolutePaths
+        # Check that repo is still clean
+        if [ ! -z "$(git status --porcelain)" ]; then
+          # If we get a fail here then the PR needs attention
+          >&2 echo "Failed: node_modules are not up to date. Run 'npm ci' and 'npm run removeNPMAbsolutePaths' to update"
+          git status
+          exit 1
+        fi
+        echo "Success: node_modules are up to date"
+
   npm-test:
     runs-on: ubuntu-latest