fix(ci): honor explicit Node versions in the test matrix

.github/actions/setup-node/action.yml

@@ -3,8 +3,8 @@ description: Sets up Node.js environment
 
 inputs:
   version:
-    description: "The version of Node.js to use"
-    default: "24.x"
+    description: "The version of Node.js to use. When omitted, detect a compatible version."
+    default: ""
     required: false
     type: string
 
@@ -22,9 +22,13 @@ runs:
       shell: bash
       env:
         npm_config_engine_strict: true
+        REQUESTED_NODE_VERSION: ${{ inputs.version }}
       run: |
+        if [ -n "${REQUESTED_NODE_VERSION}" ]; then
+          NODE_VERSION="${REQUESTED_NODE_VERSION}"
+
         # check if the installed node version works with the engines field in package.json
-        if npm ln --dry-run --ignore-scripts &>/dev/null; then
+        elif npm ln --dry-run --ignore-scripts &>/dev/null; then
           NODE_VERSION="$(node -v)"
 
         # check if .npmrc specifies a node version
@@ -43,8 +47,8 @@ runs:
         fi
 
         # check that we now have a node version, if not, use the default
-        if ! grep -qoP '^v?\d+\.(x|\d+\.)?(\d+|x)?' <<<"${NODE_VERSION}"; then
-          NODE_VERSION="${{ inputs.version || '24.x' }}"
+        if [ -z "${REQUESTED_NODE_VERSION}" ] && ! grep -qoP '^v?\d+\.(x|\d+\.)?(\d+|x)?' <<<"${NODE_VERSION}"; then
+          NODE_VERSION="24.x"
           echo "::warning::Unable to determine Node.js version from project files, using default version ${NODE_VERSION}"
         fi
 

.github/workflows/integration-test.yml

@@ -67,9 +67,9 @@ jobs:
           # step against the runner's actual npm version.
           run-install: false
 
-      - name: Build action
+      - name: Build and verify packaged entry points
         working-directory: action-under-test
-        run: npm run build
+        run: npm run test -- --run __tests__/integration-bundled-binary.test.ts
 
       - name: Checkout target repository (${{ matrix.repo }})
         uses: actions/checkout@v7.0.1

__tests__/action.test.ts

@@ -137,13 +137,27 @@ describe('Action', () => {
     });
   });
 
-  describe('nested metadata validation', () => {
+  describe('metadata validation', () => {
     const metadata = {
       name: 'Fixture action',
       description: 'Fixture description',
       runs: { using: 'node24', main: 'index.js' },
     };
 
+    it.each(['node24', 42, true])('rejects scalar runs %j with metadata context', async (runs) => {
+      vi.mocked(fs.readFileSync).mockReturnValueOnce(YAML.stringify({ ...metadata, runs }));
+      const { default: Action } = await import('../src/Action.js');
+
+      expect(() => new Action(actTestYmlPath, mockLogTask)).toThrow(
+        expect.objectContaining({
+          message: expect.stringContaining(`Failed to load ${actTestYmlPath}`),
+          cause: expect.objectContaining({
+            message: `Invalid action metadata syntax in ${actTestYmlPath}.`,
+          }),
+        }),
+      );
+    });
+
     it.each([
       { inputs: { option: null } },
       { inputs: { option: 42 } },
@@ -154,19 +168,23 @@ describe('Action', () => {
     ])('rejects malformed nested metadata through YAML loading: %j', async (nested) => {
       vi.mocked(fs.readFileSync).mockReturnValueOnce(YAML.stringify({ ...metadata, ...nested }));
       const { default: Action } = await import('../src/Action.js');
-      expect(() => new Action(actTestYmlPath, mockLogTask)).toThrow('Invalid action metadata syntax');
+      expect(() => new Action(actTestYmlPath, mockLogTask)).toThrow(
+        'Invalid action metadata syntax',
+      );
     });
 
     it('accepts scalar defaults and nullish descriptions through YAML loading', async () => {
-      vi.mocked(fs.readFileSync).mockReturnValueOnce(YAML.stringify({
-        ...metadata,
-        inputs: {
-          enabled: { description: 'Enabled', default: false, required: false },
-          retries: { description: 'Retries', default: 3 },
-          optional: { default: null, description: null },
-        },
-        outputs: { result: { description: null } },
-      }));
+      vi.mocked(fs.readFileSync).mockReturnValueOnce(
+        YAML.stringify({
+          ...metadata,
+          inputs: {
+            enabled: { description: 'Enabled', default: false, required: false },
+            retries: { description: 'Retries', default: 3 },
+            optional: { default: null, description: null },
+          },
+          outputs: { result: { description: null } },
+        }),
+      );
       const { default: Action } = await import('../src/Action.js');
       const action = new Action(actTestYmlPath, mockLogTask);
       expect(action.inputs?.enabled?.default).toBe(false);