NestModule: NestJS App Infrastructure Markdown Report Test

Overview

These tests validate nestjs-mod module architecture: module assembly via createNestModule, DI wiring, and feature configuration.

What We're Testing

• Infrastructure Mode: Ensures application can run in infrastructure documentation generation mode
• Report Generation: Verifies complete markdown report is generated with all module details
• Configuration Documentation: Tests that all static configurations and environments are documented
• Module Metadata: Confirms module descriptions, shared providers, and settings are included
• Table Formatting: Validates proper markdown table generation for configuration options

GitHub Reference

• File: utils.spec.ts
• Lines: 437-572

Setup Code

This test sets up infrastructure modules for report generation:

import { Injectable } from '@nestjs/common';
import { InfrastructureMarkdownReportGenerator, 
         InfrastructureMarkdownReportStorage,
         InfrastructureMarkdownReportStorageService } from '../modules/infrastructure/infrastructure-markdown-report/infrastructure-markdown-report';
import { DefaultNestApplicationInitializer } from '../modules/system/default-nest-application/default-nest-application-initializer';
import { DefaultNestApplicationListener } from '../modules/system/default-nest-application/default-nest-application-listener';
import { createNestModule } from '../nest-module/utils';
import { bootstrapNestApplication } from './utils';

@Injectable()
class AppReportService {
  constructor(private readonly infrastructureMarkdownReportStorage: InfrastructureMarkdownReportStorageService) {}

  getReport() {
    return this.infrastructureMarkdownReportStorage.report;
  }
}

const { App1Module } = createNestModule({
  moduleName: 'App1Module',
  imports: [InfrastructureMarkdownReportStorage.forFeature()],
  providers: [AppReportService],
});

Test Code

it('should return markdown of infrastructure', async () => {
  process.env['NESTJS_MODE'] = 'infrastructure';
  
  const app = await bootstrapNestApplication({
    project: { name: 'TestApp', description: 'Test application' },
    modules: {
      infrastructure: [
        InfrastructureMarkdownReportStorage.forRoot(),
        InfrastructureMarkdownReportGenerator.forRoot(),
      ],
      system: [
        DefaultNestApplicationInitializer.forRoot(),
        DefaultNestApplicationListener.forRoot({
          staticEnvironments: { port: 3012 },
        }),
      ],
      feature: [App1Module.forRoot()],
    },
  });

  const appReportService = app.get(AppReportService);
  expect(appReportService.getReport().split('  ').join('').split('\n').join('')).toEqual(
    `# TestApp

Test application

## System modules
System modules necessary for the operation of the entire application...

### DefaultNestApplicationInitializer
Default NestJS application initializer.

#### Static configuration
| Key| Description | Constraints | Default | Value |
| ------ | ----------- | ----------- | ------- | ----- |
| cors |CORS options...|optional|{"credentials":true...}|{"credentials":true...}|
...

## Integration modules
...

### DefaultNestApplicationListener
...

#### Static environments
| Key| Description | Sources | Constraints | Default | Value |
| ------ | ----------- | ------- | ----------- | ------- | ----- |
| port |The port...|obj['port'], process.env['TEST_APP_PORT']|optional|3000|3012|
...

## Infrastructure modules
...
`.split('  ').join('').split('\n').join('')
  );

  await app.close();
  process.env['NESTJS_MODE'] = undefined;
});

What This Test Does

1. Sets infrastructure mode via process.env['NESTJS_MODE'] = 'infrastructure'
2. Configures infrastructure modules for report storage and generation
3. Sets up system modules with custom port configuration (3012)
4. Bootstraps the application in infrastructure mode
5. Retrieves the generated report from InfrastructureMarkdownReportStorageService
6. Normalizes whitespace and compares against expected markdown structure
7. Verifies the report contains:
   • Project name and description
   • System modules with their static configurations
   • Integration modules with environments and configurations
   • Infrastructure modules with shared providers
   • Detailed tables showing keys, descriptions, sources, constraints, defaults, and values
8. Cleans up by closing the app and resetting the mode

Key Points

• This test locks the behavior contract of the target nestjs-mod block in this scenario.
• Assertions protect integration boundaries and reduce regression risk when internals evolve.