blog-be/test/app.e2e-spec.ts

import { Test, TestingModule } from '@nestjs/testing';
import { INestApplication } from '@nestjs/common';
import { AppModule } from './../src/app.module';
import { GraphQLModule } from '@nestjs/graphql';
import {
  ApolloServerTestClient,
  createTestClient,
} from 'apollo-server-testing';
import { gql } from 'apollo-server-express';

describe('ArticleResolver (e2e)', () => {
  let app: INestApplication;
  let apolloClient: ApolloServerTestClient;

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

    app = moduleFixture.createNestApplication();
    await app.init();
    const module: GraphQLModule = moduleFixture.get<GraphQLModule>(
      GraphQLModule,
    );
    // apolloServer is protected, we need to cast module to any to get it
    apolloClient = createTestClient((module as any).apolloServer);
  });
  it('QUERY hello', async () => {
    const res = await apolloClient.query({
      query: gql`
        query {
          hello {
            message
          }
        }
      `,
      variables: {},
    });
    expect(res.data).toEqual({
      hello: {
        message: 'Hello, World!',
      },
    });
  });

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