Jest + mockImplementation + Number of calls: 0 - node.js

Question

I am using Jest as testing module. Jest spy function is not called, it says Number of calls: 0.
a.test.js
const request = require('request-promise');
const moduleA = require('./a');
test('Update function', async () => {
const postSpy = jest.spyOn(request, 'post').mockImplementation((input) => input);
await moduleA();
expect(postSpy).toBeCalledWith({
method: 'POST',
uri:"fsdsfd",
headers: {
'content-type': 'application/json'
},
body: {
A:A,
B:B
},
json: true
});
});
a.js
const request = require('request-promise');
module.exports = async () => {
var options = {
method: 'POST',
uri: 'fsdsfd',
headers: {
'content-type': 'application/json',
},
body: {
A: A,
B: B,
},
json: true,
};
try {
const selectResult = await request(options);
return selectResult;
} catch (err) {
return err;
}
};
It throws error as expect(jest.fn()).toBeCalledWith(...expected) and Number of calls: 0. I think the mocked function is not called. I searched a lot regarding this but no hope. Any ideas??
EDIT
My Guess is that there is no method post in request-promise.
EDIT FOR REQUEST>POST()
request.post({
uri: 'fsdsfd',
headers: {
'content-type': 'application/json',
},
body: {
A: A,
B: B,
},
json: true,
}, function(err, resp){
if(err){
console.log(err)
} else {
console.log(resp);
return(resp)--------------->
}
});
ASYNC AWAIT EDIT
const ss = await request.post({
uri: 'fsdsfd',
headers: {
'content-type': 'application/json',
},
body: {
A: A,
B: B,
},
json: true,
});
return ss;
Here if you use this the arrow (-->) is not getting called so its not assign in test file so I can't check for result values.

Answer 1

You use request(...) instead of using request.post(...), so you need mock request function not request.post method.
E.g.
a.js:
const request = require('request-promise');
module.exports = async () => {
var options = {
uri: 'fsdsfd',
headers: {
'content-type': 'application/json',
},
body: {
A: 'A',
B: 'B',
},
json: true,
};
try {
const selectResult = await request.post(options);
return selectResult;
} catch (err) {
return err;
}
};
a.test.js:
const request = require('request-promise');
const moduleA = require('./a');
jest.mock('request-promise', () => {
return {
post: jest.fn(),
};
});
describe('59261385', () => {
afterEach(() => {
jest.resetAllMocks();
});
test('Update function', async () => {
request.post.mockResolvedValueOnce({ result: [] });
const actual = await moduleA();
expect(actual).toEqual({ result: [] });
expect(request.post).toBeCalledWith({
uri: 'fsdsfd',
headers: {
'content-type': 'application/json',
},
body: {
A: 'A',
B: 'B',
},
json: true,
});
});
});
Unit test result with coverage report:
PASS src/stackoverflow/59261385/a.test.js (11.669s)
59261385
✓ Update function (33ms)
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 87.5 | 100 | 100 | 83.33 | |
a.js | 87.5 | 100 | 100 | 83.33 | 20 |
----------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 13.599s
Source code: https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/59261385
Update:
You can use jest.spyOn too.
a.test.js:
const request = require('request-promise');
const moduleA = require('../a');
describe('59261385', () => {
afterEach(() => {
jest.restoreAllMocks();
});
test('Update function', async () => {
const postSpy = jest.spyOn(request, 'post').mockResolvedValueOnce({ result: [] });
const actual = await moduleA();
expect(actual).toEqual({ result: [] });
expect(postSpy).toBeCalledWith({
uri: 'fsdsfd',
headers: {
'content-type': 'application/json'
},
body: {
A: 'A',
B: 'B'
},
json: true
});
});
});
codesandbox: https://codesandbox.io/s/jestjs-jgye4