我如何测试具有本地依赖性的TypeORM存储库方法

Question

我是Node的新手，我正尝试用Mocha和Sinon测试TypeORM定制存储库，而无需访问数据库。

我的存储库中的方法采用2个参数并返回Promise。它使用本地查询生成器，我想对其进行侦查（queryBuilder）以了解其方法被调用了多少次。这是我的自定义存储库：

@EntityRepository(Pratica)
export class PraticaRepository extends Repository<Pratica> {

    list(targa?: string, tipoVeicolo?: string): Promise<Pratica[]> {
        fileLogger.log('info','inizio -  targa: %s; tipoVeicolo %s.', targa, tipoVeicolo);

        let queryBuilder: SelectQueryBuilder<Pratica> = this.createQueryBuilder("p")
        .leftJoinAndSelect("p.stato", "stato")
        .leftJoinAndSelect("p.microstato", "microstato");
        let filtered: boolean = false;

        if(targa && targa !== ""){
            fileLogger.debug("Applico filtro targa");
            filtered = true;
            queryBuilder.where("p.targa = :targa", {targa: targa});
        }

        if(tipoVeicolo && tipoVeicolo !== ""){
            if(!filtered){
                fileLogger.debug("Applico filtro tipoVeicolo");
                filtered = true;
                queryBuilder.where("p.tipoVeicolo = :tipoVeicolo", {tipoVeicolo: tipoVeicolo});
            }else{
                fileLogger.debug("Applico filtro tipoVeicolo come parametro aggiuntivo");
                queryBuilder.andWhere("p.tipoVeicolo = :tipoVeicolo", {tipoVeicolo: tipoVeicolo});
            }
        }

        fileLogger.log('debug', "Sql generato: %s", queryBuilder.getSql);
        fileLogger.info("fine");

        return queryBuilder.getMany();

    }

我已经尝试过以下操作：

describe('PraticaRepository#list', () => {

    it.only('should call getMany once', async () => {

        let result = new Promise((resolve,reject) => {
            resolve(new Array(new Pratica(), new Pratica()))
        });

        let getMany = sinon.stub().returns(result);

        typeorm.createQueryBuilder = sinon.stub().returns({
            select: sinon.stub(),
            from: sinon.stub(),
            leftJoinAndSelect: sinon.stub(),
            where: sinon.stub(),
            orderBy: sinon.stub(),
            getMany: getMany
          })

        let cut = new PraticaRepository();

        const appo = cut.list('','');

        sinon.assert.calledOnce(getMany);
    });
})

但是显然我得到以下错误：

1) PraticaRepository#list
       should call getMany once:
     TypeError: Cannot read property 'createQueryBuilder' of undefined
      at PraticaRepository.Repository.createQueryBuilder (src\repository\Repository.ts:50:29)
      at PraticaRepository.list (src\repositories\PraticaRepository.ts:12:62)

因为我正在存根的查询生成器不是在Repository方法中实例化的那个。我的问题：

• 是否有可能监视这样的方法？
• 此方法是否可以单元测试？还是只应该对某些功能/集成测试进行测试。

谢谢你。

Answer 1

let sandbox;
let createQueryBuilderStub;
let mock;
let fakeQueryBuilder = new SelectQueryBuilder<Pratica>(null);

beforeEach(() => {
    sandbox = sinon.createSandbox();

    mock = sandbox.mock(fakeQueryBuilder);

    createQueryBuilderStub = sandbox.stub(Repository.prototype, 
'createQueryBuilder').withArgs("p").returns(fakeQueryBuilder);
});

afterEach(() => {
    sandbox.restore();
});

describe('PraticaRepository#list', () => {

    it('should get the result with no filters', async () => {

        mock.expects('leftJoinAndSelect').twice().returns(fakeQueryBuilder);
        mock.expects('where').never();
        mock.expects('andWhere').never();
        mock.expects('getSql').once();
        mock.expects('getMany').once();

        let cut = new PraticaRepository();

        const appo = cut.list();

        sinon.assert.calledOnce(createQueryBuilderStub);
        mock.verify();

    });
})