chore: switch from jest to vitest

AGENTS.md

@@ -28,7 +28,7 @@ This is a monorepo managed with `pnpm`. It produces a CLI tool for generating hi
 - **Install**: `pnpm install`
 - **Build**: `pnpm build` (generates validators, bundles packages, and runs `tsc -b`).
 - **Lint/Format**: `pnpm lint` (uses Biome). For CI-style checks, use `pnpm ci-lint`.
-- **Unit Tests**: `pnpm test` (uses Jest). For coverage, use `pnpm ci-test`.
+- **Unit Tests**: `pnpm test` (uses Vitest). For coverage, use `pnpm ci-test`.
 - **Integration Tests**:
     - Generate: `pnpm integration:generate`
     - Validate/Build: `pnpm integration:validate`
@@ -40,9 +40,9 @@ This is a monorepo managed with `pnpm`. It produces a CLI tool for generating hi
 ## Testing Standards
 
 - **Unit Testing**: Tests are co-located with source code (`.spec.ts`).
-- **Jest Globals**: You MUST explicitly import Jest globals in test files:
+- **Vitest Globals**: You MUST explicitly import Vitest globals in test files:
   ```typescript
-  import {describe, expect, it} from "@jest/globals"
+  import {describe, expect, it} from "vitest"
   ```
 - **Regression**: Always ensure `pnpm integration:validate` passes after changes to generation logic.
 

docs/architecture.md

@@ -68,10 +68,10 @@ graph TD
 ### Invariants
 - **No `npx`**: Always use `pnpm run` or `pnpm exec`.
 - **Read-Only Generation**: Never manually edit files in `src/generated/` directories; they are overwritten during generation.
-- **Jest Globals**: Always explicitly import Jest globals (`describe`, `it`, `expect`) from `@jest/globals`.
+- **Vitest Globals**: Always explicitly import vitest globals (`describe`, `it`, `expect`) from `vitest`.
 
 ### Conventions
-- **Co-location**: Unit tests (`*.spec.ts`) are co-located with the source code they test. Use explicit jest imports (`import {describe, it, expect} from "@jest/globals"`).
+- **Co-location**: Unit tests (`*.spec.ts`) are co-located with the source code they test. Use explicit vitest imports (`import {describe, it, expect} from "vitest"`).
 - **Import Extensions**: Use `.ts` extensions in imports (e.g., `import {foo} from "./foo.ts"`) to support ESM.
 - **Dependency Migration**: Prefer `pnpm` workspace references (e.g., `"@nahkies/typescript-common-runtime": "workspace:*"`).
 

e2e/package.json

@@ -10,7 +10,7 @@
     "clean": "rm -rf ./dist && rm -rf ./src/generated",
     "generate": "./scripts/generate.sh",
     "build": "tsc -p ./tsconfig.json",
-    "test": "jest",
+    "test": "vitest run",
     "start": "node ./dist/index.js"
   },
   "dependencies": {
@@ -25,12 +25,11 @@
     "zod": "^4.3.6"
   },
   "devDependencies": {
-    "@jest/globals": "^30.4.1",
     "@nahkies/openapi-code-generator": "workspace:*",
     "@types/express": "^5.0.6",
     "@types/koa": "^3.0.3",
     "expect": "^30.4.1",
-    "jest": "^30.4.2",
-    "typescript": "^6.0.3"
+    "typescript": "^6.0.3",
+    "vitest": "^4.0.11"
   }
 }

e2e/src/index.axios.spec.ts

@@ -1,6 +1,6 @@
 import type {Server} from "node:http"
-import {afterAll, beforeAll, describe, expect, it} from "@jest/globals"
 import type {AxiosError} from "axios"
+import {afterAll, beforeAll, describe, expect, it} from "vitest"
 import {
   ApiClient,
   E2ETestClientServers,

e2e/src/index.fetch.spec.ts

@@ -7,8 +7,9 @@ import {
   describe,
   expect,
   it,
-  jest,
-} from "@jest/globals"
+  type MockedFunction,
+  vi,
+} from "vitest"
 import {
   ApiClient,
   E2ETestClientServers,
@@ -569,10 +570,10 @@ describe.each(
   })
 
   describe("route matching", () => {
-    let logSpy: jest.SpiedFunction<typeof console.log>
+    let logSpy: MockedFunction<typeof console.log>
 
     beforeEach(() => {
-      logSpy = jest.spyOn(console, "log").mockImplementation(() => {})
+      logSpy = vi.spyOn(console, "log").mockImplementation(() => {})
     })
 
     afterEach(() => {

e2e/src/test-utils.ts

@@ -1,6 +1,6 @@
 import {Blob} from "node:buffer"
-import {expect} from "@jest/globals"
 import {AsymmetricMatcher} from "expect"
+import {expect} from "vitest"
 
 class NumberInRange extends AsymmetricMatcher<number> {
   constructor(

e2e/src/vitest.d.ts

@@ -0,0 +1,10 @@
+import type {CustomMatcherResult} from "expect"
+
+declare module "vitest" {
+  interface Assertion<T = any> {
+    toEqualBlob(expected: Blob): Promise<CustomMatcherResult>
+  }
+  interface AsymmetricMatchersContaining {
+    toEqualBlob(expected: Blob): Promise<CustomMatcherResult>
+  }
+}

e2e/vitest.config.mts

@@ -0,0 +1,9 @@
+import {defineConfig} from "vitest/config"
+import {baseTestConfig} from "../vitest.base"
+
+export default defineConfig({
+  test: {
+    ...baseTestConfig.test,
+    name: "e2e",
+  },
+})

package.json

@@ -24,13 +24,13 @@
     "build": "node ./scripts/generate-ajv-validator.js && pnpm -r --workspace-concurrency=4 run bundle && tsc -b tsconfig.json",
     "build:docs": "pnpm --filter @nahkies/openapi-code-generator-documentation run build",
     "build:watch": "tsc -b tsconfig.json -w",
-    "test": "jest",
+    "test": "vitest run",
     "integration:clean": "pnpm --filter @integration/* run clean",
     "integration:generate": "node ./scripts/generate.mjs",
     "integration:validate": "pnpm -r --filter @integration/* --workspace-concurrency=2 run validate",
     "e2e:generate": "pnpm --filter e2e run clean && pnpm --filter e2e run generate",
     "e2e:validate": "pnpm --filter e2e run build && pnpm --filter e2e run test",
-    "ci-test": "jest --coverage",
+    "ci-test": "vitest run --coverage",
     "ci-lint": "biome ci .",
     "ci-pipeline": "./scripts/ci-pipeline.sh",
     "ci-pipeline:fast": "FAST=1 ./scripts/ci-pipeline.sh",
@@ -44,26 +44,24 @@
     "@biomejs/js-api": "4.0.0",
     "@biomejs/wasm-nodejs": "2.4.15",
     "@commander-js/extra-typings": "^14.0.0",
-    "@jest/reporters": "^30.4.1",
-    "@swc/core": "^1.15.40",
-    "@swc/jest": "^0.2.39",
     "@tsconfig/node24": "^24.0.4",
     "@tsconfig/strictest": "^2.0.8",
     "@types/node": "^22.19.17",
+    "@vitest/coverage-v8": "4.1.7",
     "ajv": "^8.20.0",
     "ajv-draft-04": "^1.0.0",
     "ajv-formats": "^3.0.1",
     "commander": "^14.0.3",
     "husky": "^9.1.7",
-    "jest": "^30.4.2",
     "json5": "^2.2.3",
     "lerna": "^9.0.7",
     "lint-staged": "^17.0.5",
     "prettier": "^3.8.3",
     "publint": "^0.3.21",
     "remark": "^15.0.1",
     "remark-toc": "^9.0.0",
-    "typescript": "^6.0.3"
+    "typescript": "^6.0.3",
+    "vitest": "^4.0.11"
   },
   "workspaces": [
     "packages/*",

packages/openapi-code-generator/package.json

@@ -59,14 +59,13 @@
     "clean": "rm -rf ./dist && rm -f tsconfig.tsbuildinfo",
     "build": "tsc -p ./tsconfig.json",
     "bundle": "tsdown",
-    "test": "jest"
+    "test": "vitest run"
   },
   "devDependencies": {
     "@azure-tools/typespec-autorest": "0.68.0",
     "@azure-tools/typespec-azure-core": "0.68.0",
     "@azure-tools/typespec-azure-resource-manager": "0.68.0",
     "@azure-tools/typespec-client-generator-core": "0.68.0",
-    "@jest/globals": "^30.4.1",
     "@nahkies/typescript-common-runtime": "workspace:^",
     "@types/js-yaml": "^4.0.9",
     "@types/lodash": "^4.17.24",
@@ -82,7 +81,8 @@
     "@typespec/xml": "0.82.0",
     "joi": "^18.2.1",
     "tsdown": "^0.22.0",
-    "tsx": "^4.22.3"
+    "tsx": "^4.22.3",
+    "vitest": "^4.0.12"
   },
   "dependencies": {
     "@biomejs/biome": "2.4.15",

packages/openapi-code-generator/src/core/cli-utils.spec.ts

@@ -1,4 +1,4 @@
-import {describe, expect, it} from "@jest/globals"
+import {describe, expect, it} from "vitest"
 import {
   boolParser,
   optionalBoolParser,

packages/openapi-code-generator/src/core/dependency-graph.spec.ts

@@ -1,4 +1,4 @@
-import {describe, expect, it} from "@jest/globals"
+import {describe, expect, it} from "vitest"
 import {
   createTestInputFromYamlString,
   testVersions,

packages/openapi-code-generator/src/core/loaders/generic.loader.spec.ts

@@ -1,4 +1,4 @@
-import {describe, expect, it} from "@jest/globals"
+import {describe, expect, it} from "vitest"
 import {
   type GenericLoaderRequestHeaders,
   headersForRemoteUri,

packages/openapi-code-generator/src/core/loaders/openapi-loader.spec.ts

@@ -1,4 +1,4 @@
-import {describe, expect, it} from "@jest/globals"
+import {describe, expect, it} from "vitest"
 import {normalizeRef, pathFromRef} from "./openapi-loader.ts"
 
 describe("core/openapi-loader", () => {

packages/openapi-code-generator/src/core/loaders/package.json.loader.spec.ts

@@ -1,5 +1,5 @@
 import path from "node:path"
-import {describe, expect, it} from "@jest/globals"
+import {describe, expect, it} from "vitest"
 import {NodeFsAdaptor} from "../file-system/node-fs-adaptor.ts"
 import {loadPackageJson} from "./package.json.loader.ts"
 

packages/openapi-code-generator/src/core/loaders/tsconfig.loader.spec.ts

@@ -1,4 +1,4 @@
-import {describe, expect, it, jest} from "@jest/globals"
+import {describe, expect, it, vi} from "vitest"
 import {WebFsAdaptor} from "../file-system/web-fs-adaptor.ts"
 import {loadTsConfigCompilerOptions} from "./tsconfig.loader.ts"
 
@@ -108,7 +108,7 @@ describe("core/loaders/tsconfig.loader", () => {
       }),
     })
 
-    const spy = jest
+    const spy = vi
       .spyOn(fs, "readFile")
       .mockRejectedValue(new Error("EACCES: permission denied"))
 

packages/openapi-code-generator/src/core/logger.spec.ts

@@ -1,33 +1,49 @@
-import {afterAll, beforeEach, describe, expect, it, jest} from "@jest/globals"
+import {
+  afterAll,
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  it,
+  type Mock,
+  vi,
+} from "vitest"
 import {Logger} from "./logger.ts"
 
 describe("Logger", () => {
-  let sink: {info: jest.Mock; warn: jest.Mock; error: jest.Mock}
+  let sink: {info: Mock; warn: Mock; error: Mock}
 
   beforeEach(() => {
     sink = {
-      info: jest.fn(),
-      warn: jest.fn(),
-      error: jest.fn(),
+      info: vi.fn(),
+      warn: vi.fn(),
+      error: vi.fn(),
     }
   })
 
+  afterEach(() => {
+    vi.unstubAllEnvs()
+  })
+
   afterAll(() => {
-    jest.restoreAllMocks()
+    vi.restoreAllMocks()
   })
 
   it("should include color escape sequences by default (assuming TTY)", () => {
+    vi.stubEnv("NO_COLOR", undefined)
+    vi.stubEnv("NODE_DISABLE_COLORS", undefined)
+    vi.stubEnv("TERM", "xterm")
     const logger = new Logger(true, undefined, sink)
 
     logger.warn("test message")
 
     expect(sink.warn).toHaveBeenCalledWith(
-      expect.stringContaining("\x1b[33m[warn]\x1b[0m test message"),
+      expect.stringContaining("\x1b[33m[warn]\x1b[0m test message "),
     )
   })
 
   it("should strip color escape sequences when NO_COLOR is set", () => {
-    jest.replaceProperty(process, "env", {...process.env, NO_COLOR: "1"})
+    vi.stubEnv("NO_COLOR", "1")
     const logger = new Logger(true, undefined, sink)
 
     logger.warn("test message")
@@ -36,10 +52,7 @@ describe("Logger", () => {
   })
 
   it("should strip color escape sequences when NODE_DISABLE_COLORS is set", () => {
-    jest.replaceProperty(process, "env", {
-      ...process.env,
-      NODE_DISABLE_COLORS: "1",
-    })
+    vi.stubEnv("NODE_DISABLE_COLORS", "1")
     const logger = new Logger(true, undefined, sink)
 
     logger.warn("test message")
@@ -48,7 +61,7 @@ describe("Logger", () => {
   })
 
   it("should strip color escape sequences when TERM is dumb", () => {
-    jest.replaceProperty(process, "env", {...process.env, TERM: "dumb"})
+    vi.stubEnv("TERM", "dumb")
     const logger = new Logger(true, undefined, sink)
 
     logger.warn("test message")