feat!: migrate from Jest to Vitest

Signed-off-by: Emilien Escalle <emilien.escalle@escemi.com>

Author: neilime

package-lock.json

@@ -12,7 +12,7 @@
 
 ### 📦 Package scripts
 
-- `test`: Run tests with [jest](https://jestjs.io/)
+- `test`: Run tests with [Vitest](https://vitest.dev/)
 - `lint`: Run linter with [eslint](https://eslint.org/)
 - `prepare`: Self install / update
 
@@ -38,9 +38,7 @@
 - Install and configure [eslint](https://eslint.org/) with recommended [rules](https://eslint.org/docs/rules/)
 - Configure Eslint to works with [typescript](https://github.com/typescript-eslint/typescript-eslint#readme)
 - Install and configure the following Eslint plugins:
-
   - [eslint-plugin-import](https://github.com/benmosher/eslint-plugin-import): ES2015+ (ES6+) import/export syntax
-  - [eslint-plugin-jest](https://github.com/jest-community/eslint-plugin-jest#readme): Rules for Jest
   - [eslint-plugin-node](https://github.com/mysticatea/eslint-plugin-node#readme): Additional ESLint's rules for Node.js
   - [eslint-plugin-promise](https://github.com/xjamundx/eslint-plugin-promise#readme): Enforce best practices for JavaScript promises.
 
@@ -53,13 +51,13 @@
 
 ### 🧪 Tests
 
-- Install and configure [Jest](https://jestjs.io/)
-- Install and configure [ts-jest](https://kulshekhar.github.io/ts-jest) to make Jest and Typescript work together
+- Install and configure [Vitest](https://vitest.dev/)
+- Install and configure [@vitest/coverage-v8](https://www.npmjs.com/package/@vitest/coverage-v8) for coverage reports
 
 ### 📖 Types
 
 - [@types/node](https://www.npmjs.com/package/@types/node)
-- [@types/jest](https://www.npmjs.com/package/@types/jest)
+- [vitest/globals](https://vitest.dev/config/#globals)
 
 ---
 

packages/core/README.md

@@ -34,11 +34,11 @@
     "start": "npm link && tsc -w",
     "stop": "npm unlink",
     "build": "rimraf dist && tsc",
-    "jest": "jest --detectOpenHandles --forceExit",
-    "test": "npm run jest -- --maxWorkers=50%",
-    "test:unit": "npm run test -- --testPathPattern \".+spec\\.ts\"",
-    "test:e2e": "npm run test -- --testPathPattern \".+e2e\\.spec\\.ts\"",
-    "test:coverage": "npm run test -- --coverage",
+    "vitest": "vitest",
+    "test": "vitest run",
+    "test:unit": "vitest run spec.ts",
+    "test:e2e": "vitest run e2e.spec.ts",
+    "test:coverage": "vitest run --coverage",
     "lint": "biome lint src",
     "lint:fix": "biome check --write src",
     "lint:ci": "biome check src"
@@ -48,30 +48,14 @@
   },
   "dependencies": {
     "@biomejs/biome": "^2.4.8",
+    "@vitest/coverage-v8": "^4.1.6",
     "@commitlint/cli": "^21.0.1",
     "@commitlint/config-conventional": "^21.0.2",
-    "@types/jest": "^30.0.0",
     "@types/node": "^25.9.1",
-    "jest": "^30.4.2",
-    "ts-jest": "^29.4.11",
-    "typescript": "^6.0.3"
+    "typescript": "^6.0.3",
+    "vitest": "^4.1.6"
   },
   "devDependencies": {
     "ts-node": "^10.9.2"
-  },
-  "jest": {
-    "preset": "ts-jest",
-    "testEnvironment": "node",
-    "testMatch": [
-      "**/src/**/__tests__/**/*.[jt]s?(x)",
-      "**/src/**/?(*.)+(spec|test)?(.*).+(ts|tsx|js)"
-    ],
-    "collectCoverageFrom": [
-      "**/src/**/*.[jt]s?(x)"
-    ],
-    "reporters": [
-      "default",
-      "github-actions"
-    ]
   }
 }

packages/core/package.json

@@ -1,6 +1,6 @@
-// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
-exports[`E2E - core Monorepo project Installs core package 1`] = `
+exports[`E2E - core > Monorepo project > Installs core package 1`] = `
 "Installing ts-dev-tools...
 Applying migration "core - 20201024173398-init"...
 Migration "core - 20201024173398-init" applied!
@@ -18,21 +18,17 @@ Applying migration "core - 20250623095600-remove-prettier-oxc"...
 Migration "core - 20250623095600-remove-prettier-oxc" applied!
 Applying migration "core - 20260311120000-migrate-to-biome"...
 Migration "core - 20260311120000-migrate-to-biome" applied!
+Applying migration "core - 20260604100000-migrate-to-vitest"...
+Migration "core - 20260604100000-migrate-to-vitest" applied!
 Symlinking dev dependencies...
 - Symlinking @biomejs/biome
+- Symlinking @vitest/coverage-v8
 - Symlinking @commitlint/cli
 - Symlinking @commitlint/config-conventional
-- Symlinking @types/jest
 - Symlinking @types/node
-- Symlinking jest
-- Symlinking ts-jest
+- Symlinking vitest
 Symlinking dev dependencies done!
 Resolving peer dependencies...
-- Symlinking peer dependency "@babel/core" required by "ts-jest"
-- Symlinking peer dependency "@jest/transform" required by "ts-jest"
-- Symlinking peer dependency "@jest/types" required by "ts-jest"
-- Symlinking peer dependency "babel-jest" required by "ts-jest"
-- Symlinking peer dependency "jest-util" required by "ts-jest"
 Resolving peer dependencies done!
 Checking for duplicate dev dependencies...
 Some dev dependencies are unnecessarily installed as their are already required by "@ts-dev-tools/core":
@@ -42,7 +38,7 @@ Check for duplicate dev dependencies done!
 Installation done!"
 `;
 
-exports[`E2E - core Simple project Installs core package 1`] = `
+exports[`E2E - core > Simple project > Installs core package 1`] = `
 "Installing ts-dev-tools...
 Applying migration "core - 20201024173398-init"...
 Migration "core - 20201024173398-init" applied!
@@ -60,21 +56,17 @@ Applying migration "core - 20250623095600-remove-prettier-oxc"...
 Migration "core - 20250623095600-remove-prettier-oxc" applied!
 Applying migration "core - 20260311120000-migrate-to-biome"...
 Migration "core - 20260311120000-migrate-to-biome" applied!
+Applying migration "core - 20260604100000-migrate-to-vitest"...
+Migration "core - 20260604100000-migrate-to-vitest" applied!
 Symlinking dev dependencies...
 - Symlinking @biomejs/biome
+- Symlinking @vitest/coverage-v8
 - Symlinking @commitlint/cli
 - Symlinking @commitlint/config-conventional
-- Symlinking @types/jest
 - Symlinking @types/node
-- Symlinking jest
-- Symlinking ts-jest
+- Symlinking vitest
 Symlinking dev dependencies done!
 Resolving peer dependencies...
-- Symlinking peer dependency "@babel/core" required by "ts-jest"
-- Symlinking peer dependency "@jest/transform" required by "ts-jest"
-- Symlinking peer dependency "@jest/types" required by "ts-jest"
-- Symlinking peer dependency "babel-jest" required by "ts-jest"
-- Symlinking peer dependency "jest-util" required by "ts-jest"
 Resolving peer dependencies done!
 Checking for duplicate dev dependencies...
 Some dev dependencies are unnecessarily installed as their are already required by "@ts-dev-tools/core":
@@ -84,38 +76,40 @@ Check for duplicate dev dependencies done!
 Installation done!"
 `;
 
-exports[`E2E - core Simple project Installs core package 2`] = `
+exports[`E2E - core > Simple project > Installs core package 2`] = `
 {
   "build": "tsc --noEmit",
   "check": "biome check --write .",
   "dev": "vite",
   "format": "biome format --write .",
-  "jest": "jest --detectOpenHandles --forceExit",
   "lint": "biome lint .",
   "prepare": "ts-dev-tools install",
   "preview": "vite preview",
-  "test": "npm run jest --maxWorkers=50%",
-  "test:ci": "npm run test:cov --runInBand",
-  "test:cov": "npm run test --coverage",
-  "test:watch": "npm run jest --watch --maxWorkers=25%",
+  "test": "vitest run",
+  "test:ci": "npm run test:cov",
+  "test:cov": "vitest run --coverage",
+  "test:watch": "vitest",
+  "vitest": "vitest",
 }
 `;
 
-exports[`E2E - core Simple project Installs core package 3`] = `
-{
-  "collectCoverageFrom": [
-    "**/src/**/*.[jt]s?(x)",
-  ],
-  "preset": "ts-jest",
-  "testEnvironment": "node",
-  "testMatch": [
-    "**/__tests__/**/*.[jt]s?(x)",
-    "**/?(*.)+(spec|test)?(.*).+(ts|tsx|js)",
-  ],
-}
+exports[`E2E - core > Simple project > Installs core package 3`] = `
+"import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    coverage: {
+      include: ["src/**/*.{ts,tsx,js,jsx}"],
+      provider: "v8",
+    },
+    environment: "node",
+    globals: true,
+  },
+});
+"
 `;
 
-exports[`E2E - core Simple project Installs core package 4`] = `
+exports[`E2E - core > Simple project > Installs core package 4`] = `
 "{
   "$schema": "https://biomejs.dev/schemas/__VERSION__/schema.json",
   "vcs": {

packages/core/src/__snapshots__/core.e2e.spec.ts.snap

@@ -105,7 +105,13 @@ describe(`E2E - ${packageToTest}`, () => {
       expect(packageJson.getTsDevToolsVersion()).not.toBeFalsy();
       expect(packageJson.getContent().scripts).toMatchSnapshot();
       expect(packageJson.getContent().prettier).toBeUndefined();
-      expect(packageJson.getContent().jest).toMatchSnapshot();
+      expect(packageJson.getContent().jest).toBeUndefined();
+
+      const vitestConfigFilePath = `${testProjectDir}/vitest.config.ts`;
+      expect(FileService.fileExists(vitestConfigFilePath)).toBe(true);
+      expect(
+        FileService.getFileContent(vitestConfigFilePath),
+      ).toMatchSnapshot();
 
       const biomeConfigFilePath = `${testProjectDir}/biome.json`;
       expect(FileService.fileExists(biomeConfigFilePath)).toBe(true);

packages/core/src/core.e2e.spec.ts

@@ -1,6 +1,6 @@
-// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
-exports[`Install command should run fresh installation without error 1`] = `
+exports[`Install command > should run fresh installation without error 1`] = `
 "Installing ts-dev-tools...
 Symlinking dev dependencies...
 Symlinking dev dependencies done!
@@ -12,7 +12,7 @@ Check for duplicate dev dependencies done!
 Installation done!"
 `;
 
-exports[`Install command should run update without error 1`] = `
+exports[`Install command > should run update without error 1`] = `
 "Updating ts-dev-tools installation...
 Symlinking dev dependencies...
 Symlinking dev dependencies done!

packages/core/src/install/__snapshots__/command.spec.ts.snap

@@ -196,7 +196,7 @@ describe("Migration 20260311120000-migrate-to-biome", () => {
       const invalidBiomeConfig = '{\n  "vcs":\n';
       FileService.putFileContent(biomeConfigFilePath, invalidBiomeConfig);
 
-      const warnSpy = jest.spyOn(console, "warn").mockImplementation(() => {});
+      const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
 
       try {
         await expect(up(testProjectDir)).resolves.toBeUndefined();
@@ -214,9 +214,7 @@ describe("Migration 20260311120000-migrate-to-biome", () => {
     });
 
     it("should continue when biome init does not create a config file", async () => {
-      const execCmdSpy = jest
-        .spyOn(CmdService, "execCmd")
-        .mockResolvedValue("");
+      const execCmdSpy = vi.spyOn(CmdService, "execCmd").mockResolvedValue("");
 
       try {
         await expect(up(testProjectDir)).resolves.toBeUndefined();
@@ -314,7 +312,7 @@ export default tsDevToolsCore;
       );
 
       const originalSetContent = PackageJson.prototype.setContent;
-      const setContentSpy = jest
+      const setContentSpy = vi
         .spyOn(PackageJson.prototype, "setContent")
         .mockImplementation(function mockSetContent(
           this: PackageJson,

packages/core/src/install/migrations/20260311120000-migrate-to-biome.spec.ts

@@ -0,0 +1,66 @@
+import { join } from "node:path";
+
+import { FileService } from "../../services/FileService";
+import { PackageJson } from "../../services/PackageJson";
+import {
+  createProjectForTestFile,
+  deleteTestProject,
+} from "../../tests/test-project";
+import { up as init } from "./20201024173398-init";
+import { up as migrateToBiome } from "./20260311120000-migrate-to-biome";
+import { up } from "./20260604100000-migrate-to-vitest";
+
+const useCache = true;
+const shouldCleanupAfterTest = true;
+
+describe("Migration 20260604100000-migrate-to-vitest", () => {
+  let testProjectDir: string;
+
+  beforeAll(() => {
+    if (!useCache) {
+      console.warn("Cache is disabled. Enable it one dev is done.");
+    }
+    if (!shouldCleanupAfterTest) {
+      console.warn("Cleanup is disabled. Enable it one dev is done.");
+    }
+  });
+
+  beforeEach(async () => {
+    testProjectDir = await createProjectForTestFile(__filename, useCache);
+  });
+
+  afterEach(async () => {
+    if (shouldCleanupAfterTest) {
+      await deleteTestProject(__filename);
+    }
+  });
+
+  it("should migrate generated Jest config and scripts to Vitest", async () => {
+    await init(testProjectDir);
+    await migrateToBiome(testProjectDir);
+    await up(testProjectDir);
+
+    const packageJsonContent =
+      PackageJson.fromDirPath(testProjectDir).getContent();
+
+    expect(packageJsonContent).toMatchSnapshot();
+    expect(
+      FileService.getFileContent(join(testProjectDir, "vitest.config.ts")),
+    ).toMatchSnapshot();
+  });
+
+  it("should preserve an existing custom Vitest config", async () => {
+    const vitestConfigFilePath = join(testProjectDir, "vitest.config.ts");
+    const customVitestConfig = "export default {}\n";
+
+    await init(testProjectDir);
+    await migrateToBiome(testProjectDir);
+    FileService.putFileContent(vitestConfigFilePath, customVitestConfig);
+
+    await up(testProjectDir);
+
+    expect(FileService.getFileContent(vitestConfigFilePath)).toBe(
+      customVitestConfig,
+    );
+  });
+});