After a bunch of research and experiment I've ended up with this solution. I hope it works for someone else who experienced the same issue...
- it does not need any DB connection
- testing service layer content, not the DB layer itself
- test can cover all the case I need to test without hassle, I just need to provide the right output to related typeorm methods.
This is the method I want to test
@Injectable()
export class TemplatesService {
constructor(private readonly templatesRepository: TemplatesRepository) {}
async list(filter: ListTemplatesReqDTO) {
const qb = this.templatesRepository.createQueryBuilder("tl");
const { searchQuery, ...otherFilters } = filter;
if (filter.languages) {
qb.where("tl.language IN (:...languages)");
}
if (filter.templateTypes) {
qb.where("tl.templateType IN (:...templateTypes)");
}
if (searchQuery) {
qb.where("tl.name LIKE :searchQuery", { searchQuery: `%${searchQuery}%` });
}
if (filter.skip) {
qb.skip(filter.skip);
}
if (filter.take) {
qb.take(filter.take);
}
if (filter.sort) {
qb.orderBy(filter.sort, filter.order === "ASC" ? "ASC" : "DESC");
}
return qb.setParameters(otherFilters).getManyAndCount();
}
...
}
This is the test:
import { SinonStub, createSandbox, restore, stub } from "sinon";
import * as typeorm from "typeorm";
describe("TemplatesService", () => {
let service: TemplatesService;
let repo: TemplatesRepository;
const sandbox = createSandbox();
const connectionStub = sandbox.createStubInstance(typeorm.Connection);
const templatesRepoStub = sandbox.createStubInstance(TemplatesRepository);
const queryBuilderStub = sandbox.createStubInstance(typeorm.SelectQueryBuilder);
stub(typeorm, "createConnection").resolves((connectionStub as unknown) as typeorm.Connection);
connectionStub.getCustomRepository
.withArgs(TemplatesRepository)
.returns((templatesRepoStub as unknown) as TemplatesRepository);
beforeAll(async () => {
const builder: TestingModuleBuilder = Test.createTestingModule({
imports: [
TypeOrmModule.forRoot({
type: "postgres",
database: "test",
entities: [Template],
synchronize: true,
dropSchema: true
})
],
providers: [ApiGuard, TemplatesService, TemplatesRepository],
controllers: []
});
const module = await builder.compile();
service = module.get<TemplatesService>(TemplatesService);
repo = module.get<TemplatesRepository>(TemplatesRepository);
});
beforeEach(async () => {
// do something
});
afterEach(() => {
sandbox.restore();
restore();
});
it("Service should be defined", () => {
expect(service).toBeDefined();
});
describe("list", () => {
let fakeCreateQueryBuilder;
it("should return records", async () => {
stub(queryBuilderStub, "skip" as any).returnsThis();
stub(queryBuilderStub, "take" as any).returnsThis();
stub(queryBuilderStub, "sort" as any).returnsThis();
stub(queryBuilderStub, "setParameters" as any).returnsThis();
stub(queryBuilderStub, "getManyAndCount" as any).resolves([
templatesRepoMocksListSuccess,
templatesRepoMocksListSuccess.length
]);
fakeCreateQueryBuilder = stub(repo, "createQueryBuilder" as any).returns(queryBuilderStub);
const [items, totalCount] = await service.list({});
expect(fakeCreateQueryBuilder.calledOnce).toBe(true);
expect(fakeCreateQueryBuilder.calledOnce).toBe(true);
expect(items.length).toBeGreaterThan(0);
expect(totalCount).toBeGreaterThan(0);
});
});
});
cheers!