Stubbing a specific API request inside a function - node.js

Question

How do I individually implement stubs to functions invoked inside a parent function?
Assuming I have these functions (req1,req2...) that are HTTP Requests from external services that are all returning differing values, is there a way where I can apply stubs for req1 or req2 individually to mock their values?
The purpose of this is because I need to do this to test a function that relies on an OTP verification and I want to bypass said verification in order to cover all branches in my testing.
import request from 'request-promise'
const request1 = async (data) => return request({uri: "service1.com/get", method: "GET"})
const apiRequests = async (data) => {
const req1 = await request1(data); // I want to mock this value to false
const req2 = await request2(data); // I want to mock this value to true
if (req1 && req2) {
const req3 = await request3(data);
const req4 = await request4(data);
return "Second return"
}
return "First return"
}
I've always been overwhelmed whenever trying to understand the deeper levels of mocking and most of the examples I see online aren't as nested the problem I'm facing so I'm a bit puzzled about how to go on about this.
I also work in a pretty strict setup so I'm not really allowed to use any other libraries/packages outside of Loopback's built-in testing libraries.

Answer 1

You can use stub.onCall(n) API.
Defines the behavior of the stub on the nth call. Useful for testing sequential interactions.
Besides, sinon does NOT support stub a standalone function import from a package, you need to use link seams, so that we use proxyquire package to construct seams.
E.g.
apiRequest.ts:
import request from 'request-promise';
const request1 = async (data) => request({ uri: 'service1.com/get', method: 'GET' });
export const apiRequests = async (data) => {
const req1 = await request1(data);
const req2 = await request1(data);
console.log(req1, req2);
if (req1 && req2) {
const req3 = await request1(data);
const req4 = await request1(data);
return 'Second return';
}
return 'First return';
};
apiRequest.test.ts
import proxyquire from 'proxyquire';
import sinon from 'sinon';
describe('70241641', () => {
it('should second return', async () => {
const rpStub = sinon.stub().onCall(0).resolves(true).onCall(1).resolves(true);
const { apiRequests } = proxyquire('./apiRequest', {
'request-promise': rpStub,
});
const actual = await apiRequests('test data');
sinon.assert.match(actual, 'Second return');
});
it('should first second', async () => {
const rpStub = sinon.stub().onCall(0).resolves(false).onCall(1).resolves(true);
const { apiRequests } = proxyquire('./apiRequest', {
'request-promise': rpStub,
});
const actual = await apiRequests('test data');
sinon.assert.match(actual, 'First return');
});
});
test result:
70241641
true true
✓ should second return (2374ms)
false true
✓ should first second
2 passing (2s)
---------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
---------------|---------|----------|---------|---------|-------------------
All files | 100 | 100 | 100 | 100 |
apiRequest.ts | 100 | 100 | 100 | 100 |
---------------|---------|----------|---------|---------|-------------------