EnvModel: Returns error if option of env not set

Overview

These tests validate nestjs-mod EnvModel: environment variable reading, required field validation, and DI value propagation into services.

What We Do And Verify

• We verify how envTransform and EnvModel/EnvModelProperty decorators extract and validate env values.

• We confirm expected behavior for missing or invalid required env fields.

• We lock the DI access contract for env values in services.

• We explicitly validate the error contract: not only failure itself, but also error shape/content expected by module consumers.

GitHub Reference

• File: utils.spec.ts
• Line: 8

Setup Code

import { DynamicModule, Injectable, Module } from '@nestjs/common';
import { Test, TestingModule } from '@nestjs/testing';
import { IsNotEmpty } from 'class-validator';
import { EnvModel, EnvModelProperty } from './decorators';
import { envTransform } from './utils';

describe('Env model: Utils', () => {
  // full test in the block below

});

Test Code

  it('should return error if option of env not set', async () => {
    @EnvModel()
    class AppEnv {
      @EnvModelProperty()
      @IsNotEmpty()
      option!: string;
    }

    @Module({ providers: [AppEnv] })
    class AppModule {
      static forRoot(env: Partial<AppEnv>): DynamicModule {
        return {
          module: AppModule,
          providers: [
            {
              provide: `${AppEnv.name}_loader`,
              useFactory: async (emptyAppEnv: AppEnv) => {
                if (env.constructor !== Object) {
                  Object.setPrototypeOf(emptyAppEnv, env);
                }
                const obj = await envTransform({
                  model: AppEnv,
                  data: env,
                });
                Object.assign(emptyAppEnv, obj.data);
              },
              inject: [AppEnv],
            },
          ],
        };
      }
    }

    await expect(
      Test.createTestingModule({
        imports: [AppModule.forRoot({})],
      }).compile(),
    ).rejects.toHaveProperty('errors.0.constraints.isNotEmpty', 'option should not be empty');
  });