Simple project and test case doesn't work with vitest even with the setup done according to documentation

[abnud11]

Is there an existing issue for this?

• I have searched the existing issues

Current behavior

I have these two modules:

// a.module.ts
import { Module } from '@nestjs/common';
import { BModule } from 'src/b/b.module';
import { AService } from './a.service';

@Module({
  imports: [BModule],
  providers: [AService],
  exports: [AService],
})
export class AModule {}


// b.module.ts
import { Module } from '@nestjs/common';
import { BService } from './b.service';

@Module({
  providers: [BService],
  exports: [BService],
})
export class BModule {}

And this is AppModule:

import { Module } from '@nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { AModule } from './a/a.module';

@Module({
  imports: [AModule],
  controllers: [AppController],
  providers: [AppService],
})
export class AppModule {}

AService has a dependency on BService through its constructor, BService has no dependency, AppService has a dependency on AService through its constructor too.

The above code starts successfully with pnpm start:dev and I can see that AppController responds with Hello World printed from AService .getHello method.

But in this simple test code using vitest:

import { Test } from '@nestjs/testing';
import { AppModule } from './app.module';
import { AService } from './a/a.service';
describe('AppModule', () => {
  it('resolves AService', async () => {
    const module = await Test.createTestingModule({
      imports: [AppModule],
    }).compile();
    expect(module.get(AService)).toBeDefined();
  });
});

The test code fails at the .compile line with this error:

Error: Nest can't resolve dependencies of the AService (?). Please make sure that the argument BService at index [0] is available in the AModule context.

Potential solutions:

• Is AModule a valid NestJS module?
• If BService is a provider, is it part of the current AModule?
• If BService is exported from a separate @module, is that module imported within AModule?
  @module({
  imports: [ /* the Module containing BService */ ]
  })

❯ TestingInjector.lookupComponentInParentModules node_modules/.pnpm/@nestjs+core@11.0.10_@nestjs+common@11.0.10_reflect-metadata@0.2.2_rxjs@7.8.1__@nestjs+2b60c0076d4765d97d2800d60ae176d5/node_modules/@nestjs/core/injector/injector.js:262:19
❯ TestingInjector.resolveComponentInstance node_modules/.pnpm/@nestjs+core@11.0.10@nestjs+common@11.0.10_reflect-metadata@0.2.2_rxjs@7.8.1__@nestjs+2b60c0076d4765d97d2800d60ae176d5/node_modules/@nestjs/core/injector/injector.js:215:33
❯ TestingInjector.resolveComponentInstance node_modules/.pnpm/@nestjs+testing@11.0.10@nestjs+common@11.0.10_reflect-metadata@0.2.2_rxjs@7.8.1__@nest_e6432f44fe446d0673d4fb9f30af2e0f/node_modules/@nestjs/testing/testing-injector.js:19:45
❯ resolveParam node_modules/.pnpm/@nestjs+core@11.0.10_@nestjs+common@11.0.10_reflect-metadata@0.2.2_rxjs@7.8.1__@nestjs+2b60c0076d4765d97d2800d60ae176d5/node_modules/@nestjs/core/injector/injector.js:129:38
❯ TestingInjector.resolveConstructorParams node_modules/.pnpm/@nestjs+core@11.0.10@nestjs+common@11.0.10_reflect-metadata@0.2.2_rxjs@7.8.1__@nestjs+2b60c0076d4765d97d2800d60ae176d5/node_modules/@nestjs/core/injector/injector.js:144:27
❯ TestingInjector.loadInstance node_modules/.pnpm/@nestjs+core@11.0.10@nestjs+common@11.0.10_reflect-metadata@0.2.2_rxjs@7.8.1__@nestjs+2b60c0076d4765d97d2800d60ae176d5/node_modules/@nestjs/core/injector/injector.js:70:13
❯ TestingInjector.loadProvider node_modules/.pnpm/@nestjs+core@11.0.10@nestjs+common@11.0.10_reflect-metadata@0.2.2_rxjs@7.8.1__@nestjs+2b60c0076d4765d97d2800d60ae176d5/node_modules/@nestjs/core/injector/injector.js:98:9
❯ TestingInjector.lookupComponentInImports node_modules/.pnpm/@nestjs+core@11.0.10@nestjs+common@11.0.10_reflect-metadata@0.2.2_rxjs@7.8.1__@nestjs+_2b60c0076d4765d97d2800d60ae176d5/node_modules/@nestjs/core/injector/injector.js:297:17

This is my vitest.config.mts:

import { defineConfig } from 'vitest/config';
import swc from 'unplugin-swc';
export default defineConfig({
  test: {
    globals: true,
  },
  plugins: [swc.vite({ module: { type: 'es6' } })],
});

The above is done as the documentation says here:
https://docs.nestjs.com/recipes/swc#vitest

Minimum reproduction code

https://github.com/abnud11/nestjs-vitest-problem

Steps to reproduce

1. pnpm install
2. pnpm test

Expected behavior

The test code should succeed.

Package

• I don't know. Or some 3rd-party package
• @nestjs/common
• @nestjs/core
• @nestjs/microservices
• @nestjs/platform-express
• @nestjs/platform-fastify
• @nestjs/platform-socket.io
• @nestjs/platform-ws
• @nestjs/testing
• @nestjs/websockets
• Other (see below)

Other package

No response

NestJS version

11.0.10

Packages versions

"dependencies": {
    "@nestjs/common": "^11.0.10",
    "@nestjs/core": "^11.0.10",
    "@nestjs/platform-express": "^11.0.10",
    "reflect-metadata": "^0.2.2",
    "rxjs": "^7.8.1"
  },
  "devDependencies": {
    "@eslint/eslintrc": "^3.2.0",
    "@eslint/js": "^9.20.0",
    "@nestjs/cli": "^11.0.3",
    "@nestjs/schematics": "^11.0.1",
    "@nestjs/testing": "^11.0.10",
    "@swc/cli": "^0.6.0",
    "@swc/core": "^1.10.16",
    "@types/express": "^5.0.0",
    "@types/jest": "^29.5.14",
    "@types/node": "^22.13.4",
    "@types/supertest": "^6.0.2",
    "eslint": "^9.20.1",
    "eslint-config-prettier": "^10.0.1",
    "eslint-plugin-prettier": "^5.2.3",
    "globals": "^15.15.0",
    "prettier": "^3.5.1",
    "source-map-support": "^0.5.21",
    "supertest": "^7.0.0",
    "ts-jest": "^29.2.5",
    "ts-loader": "^9.5.2",
    "ts-node": "^10.9.2",
    "tsconfig-paths": "^4.2.0",
    "typescript": "^5.7.3",
    "typescript-eslint": "^8.24.0",
    "unplugin-swc": "^1.5.1",
    "vitest": "^3.0.5"
  },
  "packageManager": "pnpm@10.4.1"

Node.js version

22.13.0

In which operating systems have you tested?

• macOS
• Windows
• Linux

Other

I'm posting this as a bug here because I think it's a documentation bug. The documentation here:
https://docs.nestjs.com/recipes/swc#vitest

It gives the impression that Vitest works and that the SWC plugin is enough, but this seems wrong. I suggest either fixing the documentation to state something extra that should be done to make the test work or just saying that vitest is not supported and explaining why.

[mag123c]

import { defineConfig } from 'vitest/config';
import swc from 'unplugin-swc';
import { resolve } from 'path';

export default defineConfig({
  test: {
    globals: true,
    root: './',
  },
  plugins: [swc.vite({ module: { type: 'es6' } })],
  resolve: {
    alias: {
      src: resolve(__dirname, './src'),
    },
  },
});

I tested this issue by comparing it with the repository you provided and was able to reproduce the same phenomenon.

Vitest does not automatically resolve src/ imports as Jest does via moduleNameMapper. By adding resolve.alias, we ensure that Vitest correctly resolves src/ references, preventing dependency resolution errors.

Would it be possible to update the documentation to include this detail? If needed, I’d be happy to submit a PR.

[kamilmysliwiec]

@mag123c yes please, PRs are more than welcome!

[mag123c]

@kamilmysliwiec I have submitted a PR to update the documentation regarding Vitest alias resolution.

Here is the PR nestjs/docs#3204.

Let me know if any adjustments are needed. Thanks!

[kamilmysliwiec]

Let's track this here nestjs/docs.nestjs.com#3204