开玩笑测试。 您如何测试来自同一模块的函数内的函数调用？

Question

I am using Jest to test in my project.

Here is my situation.

//myModule.js

export const funcA = () =>{};
export const funcB = ()=>{
  funcA();
}

//myModule.test.js
import {funcA,funcB} from './myModule'

describe("funcB",()=>{

  it ("should call funcA",
    ()=>{
     funcB(); // execute b function
     expect(funcB).toHaveBeenCalled(); // hypothetically I would like to do this. check funcA
    }
  )
});

Is there a way to achieve this? My current situation does not allow me to pass funcA as argument of funcB.

Any thoughts and ideas will be helpful! Thanks

Answer 1

Here is the unit test solution:

myModule.ts :

export let funcA = () => {};
export const funcB = () => {
  exports.funcA();
};

myModule.test.ts :

import * as mod from './myModule';

describe('funcB', () => {
  it('should call funcA', () => {
    jest.spyOn(mod, 'funcA');
    mod.funcB();
    expect(mod.funcA).toHaveBeenCalled();
  });
});

unit test results with coverage report:

 PASS  stackoverflow/60221752/myModule.test.ts (8.763s)
  funcB
    ✓ should call funcA (3ms)

-------------|---------|----------|---------|---------|-------------------
File         | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
-------------|---------|----------|---------|---------|-------------------
All files    |     100 |      100 |     100 |     100 |                   
 myModule.ts |     100 |      100 |     100 |     100 |                   
-------------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        10.308s