OverrideModule

Kind: Interface

Source: packages/testing/interfaces/override-module.interface.ts

Part of: Testing

OverrideModule defines the fluent API used to replace an existing module definition while building a test module. Calling useModule supplies a new ModuleDefinition and returns the TestingModuleBuilder so additional test configuration can be chained.

Properties

Diagram

mermaid
graph LR
  A[TestingModuleBuilder] -->|overrideModule(targetModule)| B[OverrideModule]
  B -->|useModule(newModule)| C[TestingModuleBuilder]
  C -->|compile()| D[TestingModule]

Usage

ts
import { Test } from '@nestjs/testing';
import { AppModule } from './app.module';
import { DatabaseModule } from './database.module';
import { InMemoryDatabaseModule } from './testing/in-memory-database.module';

const testingModule = await Test.createTestingModule({
  imports: [AppModule],
})
  .overrideModule(DatabaseModule)
  .useModule(InMemoryDatabaseModule)
  .compile();

AI Coding Instructions

• Use overrideModule() before calling useModule(); useModule() is available on the returned OverrideModule interface.
• Pass a valid Nest ModuleDefinition, such as a module class or supported dynamic module definition.
• Preserve the fluent builder chain by using the TestingModuleBuilder returned from useModule().
• Use module overrides for integration boundaries such as databases, messaging clients, or external-service modules.
• Ensure replacement modules provide any providers, exports, or imports required by modules under test.

Relationships

• IMPORTS → ModuleDefinition