How to stub chained functions using sinon in TypeORM - sinon

Question

I'm currently using TypeORM and Sinonjs in my project. But I'm not sure how to write the unit test in the right way. Especially how to stub a chained function call, like this
async find(id: number): Promise<User> {
const user = await this.connection
.getRepository(User)
.createQueryBuilder("user")
.where("user.id = :id", { id: id })
.getOne();
return user;
}
My test file
it('should return a data from db', async () => {
let user = {
id: 1,
name: 'my name'
};
const getOne = Sinon.stub().resolves(user);
const where = Sinon.stub().callsArg(0);
const createQueryBuilder = Sinon.stub().callsArg(0);
const connection = {
getRepository: Sinon.stub()
};
connection.getRepository.withArgs(User).returns(createQueryBuilder);
createQueryBuilder.withArgs('user').returns(where);
where.withArgs('user.id = :id', { id: user.id }).returns(getOne);
});
I always got this error
TypeError: this.connection.getRepository(...).createQueryBuilder is not a function
Any advice is welcome!
Thank you very much!

Answer 1

You should use sinon.stub(obj, 'method').returnsThis() to
Causes the stub to return its this value.
E.g.
index.ts:
type User = any;
export const model = {
connection: {
getRepository(model) {
return this;
},
createQueryBuilder(model) {
return this;
},
where(query, bindings) {
return this;
},
getOne() {
console.log('get one');
}
},
async find(id: number): Promise<User> {
const user = await this.connection
.getRepository('User')
.createQueryBuilder('user')
.where('user.id = :id', { id: id })
.getOne();
return user;
}
};
index.spec.ts:
import { model } from './';
import sinon from 'sinon';
import { expect } from 'chai';
describe('model', () => {
describe('#find', () => {
afterEach(() => {
sinon.restore();
});
it('should find user', async () => {
let mUser = {
id: 1,
name: 'my name'
};
const getRepository = sinon.stub(model.connection, 'getRepository').returnsThis();
const createQueryBuilder = sinon.stub(model.connection, 'createQueryBuilder').returnsThis();
const where = sinon.stub(model.connection, 'where').returnsThis();
const getOne = sinon.stub(model.connection, 'getOne').resolves(mUser);
const user = await model.find(1);
expect(user).to.be.eql(mUser);
expect(getRepository.calledWith('User')).to.be.true;
expect(createQueryBuilder.calledWith('user')).to.be.true;
expect(where.calledWith('user.id = :id', { id: 1 })).to.be.true;
expect(getOne.calledOnce).to.be.true;
});
});
});
Unit test result with coverage report:
model
#find
✓ should find user
1 passing (13ms)
---------------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
---------------|----------|----------|----------|----------|-------------------|
All files | 86.21 | 100 | 55.56 | 84.62 | |
index.spec.ts | 100 | 100 | 100 | 100 | |
index.ts | 50 | 100 | 20 | 42.86 | 6,9,12,15 |
---------------|----------|----------|----------|----------|-------------------|
Source code: https://github.com/mrdulin/mocha-chai-sinon-codelab/tree/master/src/stackoverflow/57843415