Jest mocking multiple files and static methods - node.js

Question

I am trying to write a test case using Jest. How can I write the test case for below snippets? A is a separate file and Three is a different file. I need to write the test cases as separate files as like unit test cases.
I am stuck in writing the static methods calling and mocking the multiple inputs. See below what I have tried also.
const one = require('../one');
const two = require('../two');
const three = require('../three');
class A {
public static checkTesting(param) {
switch (param) {
case 'one':
return one;
case 'two':
return two;
default:
return three;
}
}
constructor(param) {
this.testing = A.checkTesting(param);
}
}
module.exports = A;
const multiple = require('../multiple')(module);
const config = require('../config');
class Three {
public static sampleTestingWrite() {
return {
b: param => multiple[config.access](param)
};
}
constructor() {
this.sampleTesting = Three.sampleTestingWrite();
}
}
module.exports = Three;
A.test.js:
const One = require('../one');
const Two = require('../two');
const Three = require('../three');
const A = require('..');
jest.mock('../one');
jest.mock('../two');
jest.mock('../three');
describe('A test cases', () => {
test('should initiate the constructor', () => {
const mockStaticFunction = jest.fn();
mockStaticFunction.mockReturnValue('returns an object which does something on Multiple');
const MockA = new A('one');
console.log(MockA);
Console.mockImplementation(() => ({}));
console.log(logMedium);
expect(Console).toHaveBeenCalledTimes(1);
});
});

Answer 1

If you want to test if the constructor of A is called correctly. There is no need to mock one, two, three modules. Only you need to mock/spyOn is
checkTesting static method of A.
Here is the solution, I use typescript
import one from './one';
import two from './two';
import three from './three';
class A {
public static checkTesting(param) {
switch (param) {
case 'one':
return one;
case 'two':
return two;
default:
return three;
}
}
private testing;
constructor(param) {
this.testing = A.checkTesting(param);
}
}
export { A };
Unit test:
import { A } from './a';
describe('A', () => {
describe('checkTesting', () => {
it('should initiate the constructor', () => {
jest.spyOn(A, 'checkTesting').mockReturnValue({ name: 'never mind' });
const param = 'one';
const a = new A(param);
expect(a).toBeInstanceOf(A);
expect(A.checkTesting).toBeCalledWith(param);
});
});
});
Unit test result with coverage:
PASS src/mock-function/57624975/a.spec.ts
A
checkTesting
✓ t1 (8ms)
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 73.33 | 0 | 66.67 | 73.33 | |
a.ts | 66.67 | 0 | 66.67 | 66.67 | 7,9,11,13 |
one.ts | 100 | 100 | 100 | 100 | |
three.ts | 100 | 100 | 100 | 100 | |
two.ts | 100 | 100 | 100 | 100 | |
----------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 1.649s, estimated 3s