TestingModule

Kind: Class

Source: packages/testing/testing-module.ts

Part of: Testing

TestingModule is the compiled test container returned by Nest's testing utilities. It provides access to resolved providers and exposes factory methods for creating test-specific Nest HTTP applications or microservices from the module configuration.

Extends: NestApplicationContext

Methods

Properties

Where it refuses work

• TestingModule stops the work with an early return when !options || isUndefined(options.logger).
• TestingModule stops the work with an early return when !(prop in receiver) && prop in adapter.

Diagram

mermaid
graph LR
  A[Test.createTestingModule] --> B[TestingModuleBuilder]
  B --> C[TestingModule]
  C --> D[Resolve providers with get/resolve]
  C --> E[createNestApplication]
  C --> F[createNestMicroservice]
  E --> G[INestApplication]
  F --> H[INestMicroservice]

Usage

ts
import { Test } from '@nestjs/testing';
import { INestApplication } from '@nestjs/common';
import { AppModule } from '../src/app.module';

describe('AppModule', () => {
  let app: INestApplication;

  beforeAll(async () => {
    const moduleRef = await Test.createTestingModule({
      imports: [AppModule],
    }).compile();

    app = moduleRef.createNestApplication();
    await app.init();
  });

  afterAll(async () => {
    await app.close();
  });

  it('starts the application', async () => {
    expect(app).toBeDefined();
  });
});

AI Coding Instructions

• Build and compile a testing module with Test.createTestingModule(...).compile() before calling createNestApplication() or createNestMicroservice().
• Use moduleRef.get() or moduleRef.resolve() to retrieve and test providers directly when an HTTP server is unnecessary.
• Always call await app.init() before sending requests to an application created by createNestApplication().
• Close created applications or microservices in teardown hooks to prevent open handles between test suites.
• Override providers, guards, or modules on the testing module builder before calling compile() to isolate external dependencies.

How it works

TestingModule is the testing package’s exported application-context class. It extends NestApplicationContext, retaining context operations such as dependency lookup, scoped resolution, lifecycle initialization, and shutdown; it is returned by TestingModuleBuilder.compile() after dependency scanning, instance creation, and application-provider setup. packages/testing/testing-module.ts:26 packages/testing/testing-module.builder.ts:97-131 packages/core/nest-application-context.ts:165-175 packages/core/nest-application-context.ts:226-245 packages/core/nest-application-context.ts:253-284

Its constructor receives a Nest container, graph inspector, context module, application configuration, and optional module scope. It initializes the inherited context with empty context options, stores the supplied graph inspector, and passes the supplied context module and scope to the parent context. packages/testing/testing-module.ts:29-40

Relationships

• IMPORTS → HttpServer
• IMPORTS → INestApplication
• IMPORTS → INestMicroservice
• IMPORTS → Logger
• IMPORTS → NestApplicationOptions
• IMPORTS → Type
• IMPORTS → NestMicroserviceOptions
• IMPORTS → NestApplicationContextOptions
• IMPORTS → loadPackage
• IMPORTS → isUndefined
• IMPORTS → AbstractHttpAdapter
• IMPORTS → NestApplication
• IMPORTS → NestApplicationContext
• IMPORTS → ApplicationConfig
• IMPORTS → NestContainer
• IMPORTS → Module
• IMPORTS → GraphInspector
• IMPORTS → -nestjs-microservices
• IMPORTS → -nestjs-platform-express