Add real VS Code integration smoke test

.github/workflows/test.yml

@@ -64,3 +64,49 @@ jobs:
           unzip -Z1 liquid-java.vsix > /tmp/liquid-java-vsix-files.txt
           grep -Fx 'extension/dist/server/language-server-liquidjava.jar' /tmp/liquid-java-vsix-files.txt
           grep -Fx 'extension/media/webview.js' /tmp/liquid-java-vsix-files.txt
+
+  integration:
+    name: VS Code integration
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
+    runs-on: ubuntu-latest
+
+    defaults:
+      run:
+        working-directory: client
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Java
+        id: java
+        uses: actions/setup-java@v4
+        with:
+          java-version: 21
+          distribution: temurin
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+          cache-dependency-path: client/package-lock.json
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build server
+        run: npm run build:server
+
+      - name: Run VS Code stable smoke test
+        env:
+          JAVA_HOME: ${{ steps.java.outputs.path }}
+        run: xvfb-run -a npm test
+
+      - name: Upload VS Code logs
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: vscode-logs
+          path: client/.vscode-test/user-data/logs
+          if-no-files-found: ignore

client/.gitignore

@@ -3,4 +3,5 @@ node_modules
 yarn.lock
 *.vsix
 media/*.js
-media/*.js.map
+media/*.js.map
+.vscode-test/

client/.vscode-test.mjs

@@ -0,0 +1,10 @@
+import { defineConfig } from '@vscode/test-cli';
+
+export default defineConfig({
+    files: 'out/test/**/*.test.js',
+    version: 'stable',
+    workspaceFolder: 'test-fixtures/failing',
+    extensionDevelopmentPath: '.',
+    launchArgs: ['--disable-extensions', '--disable-workspace-trust'],
+    mocha: { ui: 'tdd', timeout: 120_000 },
+});

client/.vscodeignore

@@ -5,7 +5,7 @@
 src/**
 eslint.config.mjs
 .gitignore
-tsconfig.json
+tsconfig*.json
 webpack.config.js
 vsc-extension-quickstart.md
 package-lock.json
@@ -42,3 +42,6 @@ server/**
 **/.DS_Store
 *.log
 npm-debug.log*
+
+.vscode-test.mjs
+test-fixtures/**