Testing Microservice client and `Cannot read property 'send' of null`

I’m trying to test microservice and his client controller

// client
@Controller()
export class EnvironmentRpcClientController {

  @Client({ transport: Transport.TCP, port: ENVIRONMENT_APP_CONFIG.rpcPort })
  private client: ClientProxy;


  public get<T extends Object>(moduleName?: string): Observable<T> {

    const pattern = ENVIRONMENT_RPC_CONFIG.actions.get;
    const data = moduleName;

    return this.client.send<T>(pattern, data);
  }
}

test (EnvironmentAppModule is main microservice module with RPC server)

import { Test } from '@nestjs/testing';
import { NestFactory } from '@nestjs/core';
import 'rxjs/add/operator/finally';

import { ENVIRONMENT_APP_CONFIG } from '../src/config';
import { EnvironmentAppModule } from '../src/module';


import { EnvironmentRpcClientController } from '../src/rpc';


describe('environment', () => {

  let serverApp: any;

  let environmentRpcClientController: EnvironmentRpcClientController;


  beforeEach(done => {

    serverApp = NestFactory.createMicroservice(EnvironmentAppModule, { port: ENVIRONMENT_APP_CONFIG.rpcPort });

    serverApp.listen(() => {

      (<any> serverApp).logger.log(`TEST RPC server is listening on port ${ENVIRONMENT_APP_CONFIG.rpcPort}`);


      Test.createTestingModule({
        controllers: [ EnvironmentRpcClientController ],
      });

      environmentRpcClientController = Test.get(EnvironmentRpcClientController);

      done();
    });
  });

  afterEach(done => {

    serverApp.server.server.close(() => done());
  });


  it('should request envinroment data from service', done => {

    environmentRpcClientController.get()
      .finally(() => done())
      .subscribe(
        config => console.log('config', config)
      );
  });
});

and as result

    TypeError: Cannot read property 'send' of null

this.client in EnvironmentRpcClientController.get() is null.

Also i’m forced to use private fields access hacks like serverApp.server.server.close() to shutdown RPC server after each test and before new one, public method for server close will be cool.

[kamilmysliwiec]

Hey guys, In the nearest release it’d be possible to override components from imported modules. It should help with testing those scenarios.

[artaommahe]

@ThomRick

I don’t how you can call your microservice client controller with an external event / message (like an http request for example)

service without any public endpoint that has some tasks by interval, including RPC calls ) RPC client can be defined in service for this purpose.

Thx for your analysis, will wait for nest update for this tests 😃