Migrate to Vitest

Author: Mrtenz

eslint.config.mjs

@@ -1,7 +1,7 @@
 import base, { createConfig } from '@metamask/eslint-config';
-import jest from '@metamask/eslint-config-jest';
 import nodejs from '@metamask/eslint-config-nodejs';
 import typescript from '@metamask/eslint-config-typescript';
+import vitest from '@metamask/eslint-config-vitest';
 
 const config = createConfig([
   {
@@ -40,7 +40,7 @@ const config = createConfig([
 
   {
     files: ['**/*.test.ts', '**/*.test.js'],
-    extends: [jest, nodejs],
+    extends: [vitest, nodejs],
   },
 ]);
 

jest.config.js

@@ -41,41 +41,41 @@
     "lint:fix": "yarn lint:eslint --fix && yarn lint:constraints --fix && yarn lint:misc --write && yarn lint:dependencies && yarn lint:changelog",
     "lint:misc": "prettier '**/*.json' '**/*.md' '**/*.yml' '!.yarnrc.yml' --ignore-path .gitignore --no-error-on-unmatched-pattern",
     "prepack": "./scripts/prepack.sh",
-    "test": "jest && jest-it-up && attw --pack",
-    "test:watch": "jest --watch"
+    "test": "vitest && attw --pack",
+    "test:watch": "vitest --watch"
   },
   "devDependencies": {
     "@arethetypeswrong/cli": "^0.15.3",
     "@lavamoat/allow-scripts": "^3.0.4",
     "@lavamoat/preinstall-always-fail": "^2.0.0",
     "@metamask/auto-changelog": "^4.0.0",
     "@metamask/eslint-config": "^14.0.0",
-    "@metamask/eslint-config-jest": "^14.0.0",
     "@metamask/eslint-config-nodejs": "^14.0.0",
     "@metamask/eslint-config-typescript": "^14.0.0",
+    "@metamask/eslint-config-vitest": "^1.0.0",
     "@ts-bridge/cli": "^0.6.3",
-    "@types/jest": "^28.1.6",
     "@types/node": "^18.18",
+    "@vitest/coverage-istanbul": "^3.0.7",
+    "@vitest/eslint-plugin": "^1.1.4",
     "@yarnpkg/types": "^4.0.0-rc.52",
     "depcheck": "^1.4.3",
     "eslint": "^9.11.0",
     "eslint-config-prettier": "^9.1.0",
     "eslint-import-resolver-typescript": "^3.6.3",
     "eslint-plugin-import-x": "^4.3.0",
-    "eslint-plugin-jest": "^28.8.3",
     "eslint-plugin-jsdoc": "^50.2.4",
     "eslint-plugin-n": "^17.10.3",
     "eslint-plugin-prettier": "^5.2.1",
     "eslint-plugin-promise": "^7.1.0",
-    "jest": "^28.1.3",
-    "jest-it-up": "^2.0.2",
     "prettier": "^3.3.3",
-    "prettier-plugin-packagejson": "^2.3.0",
+    "prettier-plugin-packagejson": "^2.5.8",
     "ts-jest": "^28.0.7",
     "ts-node": "^10.7.0",
     "typedoc": "^0.26.11",
-    "typescript": "~5.4.5",
-    "typescript-eslint": "^8.6.0"
+    "typescript": "~5.7.3",
+    "typescript-eslint": "^8.6.0",
+    "vite": "^6.2.0",
+    "vitest": "^3.0.7"
   },
   "packageManager": "[email protected]",
   "engines": {
@@ -87,7 +87,8 @@
   },
   "lavamoat": {
     "allowScripts": {
-      "@lavamoat/preinstall-always-fail": false
+      "@lavamoat/preinstall-always-fail": false,
+      "vite>esbuild": false
     }
   }
 }

package.json

@@ -0,0 +1,9 @@
+import { describe, it, expectTypeOf } from 'vitest';
+
+import greeter from '.';
+
+describe('greeter', () => {
+  it('returns a string', () => {
+    expectTypeOf(greeter('Huey')).toEqualTypeOf<string>();
+  });
+});

src/index.test-d.ts

@@ -1,6 +1,8 @@
+import { describe, it, expect } from 'vitest';
+
 import greeter from '.';
 
-describe('Test', () => {
+describe('greeter', () => {
   it('greets', () => {
     const name = 'Huey';
     const result = greeter(name);

src/index.test.ts

@@ -0,0 +1,22 @@
+{
+  "compilerOptions": {
+    "esModuleInterop": true,
+    "exactOptionalPropertyTypes": true,
+    "forceConsistentCasingInFileNames": true,
+    "lib": ["ES2023"],
+    "module": "ES2022",
+    "moduleResolution": "Bundler",
+    "noEmit": true,
+    "noErrorTruncation": true,
+    "noUncheckedIndexedAccess": true,
+    "skipLibCheck": true,
+    "skipDefaultLibCheck": true,
+    "strict": true,
+    "target": "ES2023"
+  },
+  "include": [
+    "./src/**/*.test.ts",
+    "./src/**/*.test-d.ts"
+  ],
+  "exclude": ["./dist", "**/node_modules"]
+}

tsconfig.test.json

@@ -0,0 +1,54 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    // Vitest enables watch mode by default. We disable it here, so it can be
+    // explicitly enabled with `yarn test:watch`.
+    watch: false,
+
+    // The files to include in the test run.
+    include: ['src/**/*.test.ts'],
+
+    coverage: {
+      enabled: true,
+
+      // Configure the coverage provider. We use `istanbul` here, because it
+      // is more stable than `v8`.
+      provider: 'istanbul',
+
+      // The files to include in the coverage report.
+      include: [
+        'src/**/*.ts',
+        'src/**/*.tsx',
+        'src/**/*.js',
+        'src/**/*.jsx',
+        'src/**/*.mjs',
+      ],
+
+      // The files to exclude from the coverage report. Vitest excludes test
+      // files by default, but not `test-d.ts` files.
+      exclude: ['src/**/*.test-d.ts'],
+
+      // Coverage thresholds. If the coverage is below these thresholds, the
+      // test will fail.
+      thresholds: {
+        // Auto-update the coverage thresholds. When this is enabled, the
+        // thresholds will be updated automatically when the coverage is
+        // above the current thresholds.
+        autoUpdate: true,
+
+        branches: 100,
+        functions: 100,
+        lines: 100,
+        statements: 100,
+      },
+    },
+
+    typecheck: {
+      enabled: true,
+
+      // The path to the tsconfig file to use for type checking.
+      tsconfig: './tsconfig.test.json',
+    },
+  },
+});