How to thrown error in catch block using sinon stub - node.js

Question

I am using mocha and sinon for test the node services, In controller I have getToken npm module for getting the token with name and value as parameters and in spec file I trying to send empty name as parameter using withargs but the response getting success excepted result is token creating fail please help on this issue.
controller.ts
import {getToken} from './tokenUtil';
export async function userInfo(req:Request,res:Response){
try{
let token = await getToken(name,value);
}
catch(error){
res.send({status:'Failue',message:error});
return
}
res.send({status:'success',message:'token creation success'})
}
tokenUtil.ts
export async function getToken(name,value){
// token code here
}
token.spce.ts
import * as sinon from 'sinon';
import * as proxyquire from 'proxyquire';
describe('get token',()=>{
let req:any;
let res:any;
beforeEach(()=>{
res={
send:sinon.stub();
}
it('getting error when given empty name',async()=>{
let tokenStub = sinon.stub().withArgs('',tokenValue).returns(undefined);
let tokenctl=proxyquire('./controller',{
'./tokenUtil':tokenStub
})
await tokenctl.userInfo(req,res);
sinon.assert.calledWithExactly(res.send,{status:'Failue',message:'token creating fail'})
})
})
})

Answer 1

You are testing the controller.ts module, so the test file name should be controller.spec.ts or controller.test.ts.
Since the ./tokenUtil use named exports, so the tokenStub should be an object.
You should use sinon.stub().rejects() to create a promise stub with rejected value.
E.g.
controller.ts:
import { getToken } from './tokenUtil';
import { Request, Response } from 'express';
export async function userInfo(req: Request, res: Response) {
const { name, value } = req.body;
try {
let token = await getToken(name, value);
res.send({ status: 'success', message: 'token creation success' });
} catch (error) {
res.send({ status: 'Failue', message: error });
}
}
tokenUtil.ts:
export async function getToken(name, value) {
// token code here
}
controller.test.ts:
import sinon from 'sinon';
import proxyquire from 'proxyquire';
describe('get token', () => {
let req: any;
let res: any;
beforeEach(() => {
res = {
send: sinon.stub(),
};
});
it('should create token success', async () => {
req = { body: { value: '123', name: 'teresa teng' } };
let tokenStub = {
getToken: sinon.stub().withArgs(req.body.name, req.body.value).resolves(),
};
let tokenctl = proxyquire('./controller', {
'./tokenUtil': tokenStub,
});
await tokenctl.userInfo(req, res);
sinon.assert.calledWithExactly(res.send, { status: 'success', message: 'token creation success' });
});
it('should handle error when given empty name', async () => {
const tokenValue = '123';
req = { body: { value: tokenValue, name: '' } };
const error = new Error('token creating fail');
let tokenStub = {
getToken: sinon.stub().withArgs('', tokenValue).rejects(error),
};
let tokenctl = proxyquire('./controller', {
'./tokenUtil': tokenStub,
});
await tokenctl.userInfo(req, res);
sinon.assert.calledWithExactly(res.send, { status: 'Failue', message: error });
});
});
Test result:
get token
✓ should create token success (101ms)
✓ should handle error when given empty name
2 passing (112ms)