Migrate from Mocha to Vitest (#2789)

Author: 2nofa11

.vscode/launch.json

@@ -5,9 +5,17 @@
       "type": "node",
       "request": "launch",
       "name": "Start testing",
-      "program": "${workspaceFolder}/node_modules/.bin/mocha",
-      "args": ["${file}", "--watch"],
+      "program": "${workspaceFolder}/node_modules/.bin/vitest",
+      "args": ["run", "${file}", "--reporter=verbose"],
+      "console": "integratedTerminal"
+    },
+    {
+      "type": "node",
+      "request": "launch",
+      "name": "Start testing (watch)",
+      "program": "${workspaceFolder}/node_modules/.bin/vitest",
+      "args": ["${file}", "--reporter=verbose"],
       "console": "integratedTerminal"
     }
   ]
-}
+}

eslint.config.mjs

@@ -77,7 +77,7 @@ export default typegen([
       globals: {
         ...globals.es6,
         ...globals.node,
-        ...globals.mocha
+        ...globals.vitest
       }
     },
     linterOptions: {

package.json

@@ -7,13 +7,13 @@
   "scripts": {
     "new": "node tools/new-rule.js",
     "start": "npm run test:base -- --watch --growl",
-    "test:base": "mocha \"tests/lib/**/*.js\" --reporter dot",
-    "test": "nyc npm run test:base -- \"tests/integrations/*.js\" --timeout 60000",
-    "test:integrations": "mocha \"tests/integrations/*.js\" --timeout 60000",
-    "debug": "mocha --inspect \"tests/lib/**/*.js\" --reporter dot --timeout 60000",
+    "test:base": "vitest run --reporter=dot tests/lib",
+    "test": "vitest run",
+    "test:integrations": "vitest run tests/integrations",
+    "debug": "vitest run --inspect --no-file-parallelism --reporter=dot tests/lib",
     "cover": "npm run cover:test && npm run cover:report",
-    "cover:test": "nyc npm run test:base -- --timeout 60000",
-    "cover:report": "nyc report --reporter=html",
+    "cover:test": "vitest run --coverage --reporter=dot tests/lib",
+    "cover:report": "echo 'HTML coverage report available at ./coverage/index.html'",
     "lint": "eslint . && markdownlint \"**/*.md\"",
     "lint:fix": "eslint . --fix && markdownlint \"**/*.md\" --fix",
     "tsc": "tsc",
@@ -87,6 +87,7 @@
     "@types/xml-name-validator": "^4.0.3",
     "@typescript-eslint/parser": "^8.35.1",
     "@typescript-eslint/types": "^8.35.1",
+    "@vitest/coverage-v8": "^3.2.4",
     "assert": "^2.1.0",
     "env-cmd": "^10.1.0",
     "esbuild": "^0.24.0",
@@ -106,8 +107,6 @@
     "globals": "^15.14.0",
     "jsdom": "^22.0.0",
     "markdownlint-cli": "^0.42.0",
-    "mocha": "^10.7.3",
-    "nyc": "^17.1.0",
     "pathe": "^1.1.2",
     "prettier": "^3.3.3",
     "typescript": "^5.7.2",

tests/.eslintrc.json

@@ -9,18 +9,12 @@ const cp = require('child_process')
 const path = require('path')
 const semver = require('semver')
 
+const PLUGIN_DIR = path.join(__dirname, 'eslint-plugin-import')
 const ESLINT = `.${path.sep}node_modules${path.sep}.bin${path.sep}eslint`
 
 describe('Integration with eslint-plugin-import', () => {
-  let originalCwd
-
-  before(() => {
-    originalCwd = process.cwd()
-    process.chdir(path.join(__dirname, 'eslint-plugin-import'))
-    cp.execSync('npm i', { stdio: 'inherit' })
-  })
-  after(() => {
-    process.chdir(originalCwd)
+  beforeAll(() => {
+    cp.execSync('npm i', { cwd: PLUGIN_DIR, stdio: 'inherit' })
   })
 
   // https://github.com/vuejs/eslint-plugin-vue/issues/21#issuecomment-308957697
@@ -41,6 +35,6 @@ describe('Integration with eslint-plugin-import', () => {
       return
     }
 
-    cp.execSync(`${ESLINT} a.vue`, { stdio: 'inherit' })
+    cp.execSync(`${ESLINT} a.vue`, { cwd: PLUGIN_DIR, stdio: 'inherit' })
   })
 })

tests/integrations/eslint-plugin-import.js

@@ -5,18 +5,12 @@ const cp = require('child_process')
 const path = require('path')
 const semver = require('semver')
 
+const TARGET_DIR = path.join(__dirname, 'flat-config')
 const ESLINT = `.${path.sep}node_modules${path.sep}.bin${path.sep}eslint`
 
 describe('Integration with flat config', () => {
-  let originalCwd
-
-  before(() => {
-    originalCwd = process.cwd()
-    process.chdir(path.join(__dirname, 'flat-config'))
-    cp.execSync('npm i -f', { stdio: 'inherit' })
-  })
-  after(() => {
-    process.chdir(originalCwd)
+  beforeAll(() => {
+    cp.execSync('npm i -f', { cwd: TARGET_DIR, stdio: 'inherit' })
   })
 
   it('should lint without errors', () => {
@@ -33,6 +27,7 @@ describe('Integration with flat config', () => {
 
     const result = JSON.parse(
       cp.execSync(`${ESLINT} a.vue --format=json`, {
+        cwd: TARGET_DIR,
         encoding: 'utf8'
       })
     )

tests/integrations/flat-config.js

@@ -0,0 +1,32 @@
+
+import { defineConfig } from 'vitest/config';
+export default defineConfig({
+  test: {
+    include: [
+      'tests/lib/**/*.js',
+      'tests/integrations/**/*.js'
+    ],
+    exclude: [
+      '**/node_modules/**',
+      '**/dist/**',
+      'tests/fixtures/**',
+      'tests/integrations/flat-config/eslint.config.js',
+      'tests/lib/rules/no-unsupported-features/utils.js'
+    ],
+    testTimeout: 60_000,
+    globals: true,
+    coverage: {
+      provider: 'v8',
+      include: ['lib/**/*.js'],
+      exclude: [
+        'tests/**',
+        'dist/**',
+        'tools/**',
+        'node_modules/**'
+      ],
+      reporter: ['text', 'lcov', 'json-summary', 'html'],
+      all: true,
+      reportsDirectory: './coverage'
+    },
+  },
+});