test(editor): add test setup (#7361)

Tried it with `vitest`, but there was too many problems with `vscode`
integration.
That why I followed the official guide:
-
https://code.visualstudio.com/api/working-with-extensions/testing-extension#migrating-from-vscode
-
https://code.visualstudio.com/api/working-with-extensions/continuous-integration

.github/workflows/ci_vscode.yml

@@ -45,3 +45,14 @@ jobs:
       - name: Lint VSCode
         working-directory: editors/vscode
         run: pnpm run lint
+
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: taiki-e/checkout-action@v1
+      - uses: ./.github/actions/pnpm
+
+      - name: Test VSCode
+        working-directory: editors/vscode
+        run: xvfb-run -a pnpm run test

.gitignore

@@ -11,6 +11,7 @@ target/
 /tasks/compat_data/node_modules/
 
 # vscode
+/editors/vscode/.vscode-test/
 /editors/vscode/node_modules/
 /editors/vscode/icon.png
 /editors/vscode/out/

editors/vscode/.vscode-test.mjs

@@ -0,0 +1,5 @@
+import { defineConfig } from '@vscode/test-cli';
+
+export default defineConfig({
+  files: 'out/**/*.spec.js',
+});

editors/vscode/client/config.spec.ts

@@ -0,0 +1,12 @@
+import { strictEqual } from 'assert';
+import { ConfigService } from './config.js';
+
+suite('default values on initialization', () => {
+  const service = new ConfigService();
+
+  strictEqual(service.runTrigger, 'onType');
+  strictEqual(service.enable, true);
+  strictEqual(service.trace, 'off');
+  strictEqual(service.configPath, '.eslintrc');
+  strictEqual(service.binPath, '');
+});

editors/vscode/package.json

@@ -136,11 +136,15 @@
     "install-extension": "code --install-extension oxc_language_server.vsix --force",
     "server:build:debug": "cargo build -p oxc_language_server",
     "server:build:release": "cross-env CARGO_TARGET_DIR=./target cargo build -p oxc_language_server --release",
-    "lint": "npx oxlint --config=oxlint.json --tsconfig=tsconfig.json"
+    "lint": "npx oxlint --config=oxlint.json --tsconfig=tsconfig.json",
+    "test": "esbuild client/config.spec.ts --bundle --outfile=out/config.spec.js --external:vscode --format=cjs --platform=node --target=node16 --minify --sourcemap && vscode-test"
   },
   "devDependencies": {
+    "@types/mocha": "^10.0.9",
     "@types/node": "^22.0.0",
     "@types/vscode": "1.95.0",
+    "@vscode/test-cli": "^0.0.10",
+    "@vscode/test-electron": "^2.4.1",
     "@vscode/vsce": "^3.0.0",
     "cross-env": "^7.0.3",
     "esbuild": "^0.24.0",