Why doesn't the mockAxios.post.mockImplementationOnce return any data

Question

Why doesn't the mockAxios.post.mockImplementationOnce return any data? I would like to see the errors.

  it('should show errors when submitting returns a 422 response', () => {
    mockAxios.post.mockImplementationOnce(() =>
      Promise.resolve({
        data: { errors: ['Name is required.', 'Email is required.'] },
        status: 422,
      })
    )

    addStudentForm()
      .find('button.open-modal')
      .simulate('click')
    addStudentForm()
      .find('button.submit')
      .simulate('click')

    expect(addStudentForm().instance().state.showModal).toBe(true)
    console.log(addStudentForm().instance().state)
  })

This is my state as it's there in the console.log.

{ showModal: true,
 name: '',
 username: '' }

On the frontend the response in event.response.data does show me what I want to see what I expect errors :["Name is required.", "Email is required."] but I cannot seem to mock it.

If you needed to see full context: https://github.com/freeCodeCamp/classroom-mode/blob/mock-axio/client/src/test/AddStudentForm.test.js

Interesting enough when I have the await on the

await addStudentForm()
  .find('button.submit')
  .simulate('click') 

The expect(addStudentForm().instance().state.showModal).toBe(true) returns false.

Answer 1

You seems to miss done(), and that's why test is finished earlier then mocked data returned:

it('should show errors when submitting returns a 422 response', done // < --HERE ->
=> {
    mockAxios.post.mockImplementationOnce(() => {
      Promise.resolve({
        data: { errors: ['Name is required.', 'Email is required.'] },
        status: 422,
      });

    addStudentForm()
      .find('button.open-modal')
      .simulate('click')
    addStudentForm()
      .find('button.submit')
      .simulate('click')

    expect(addStudentForm().instance().state.showModal).toBe(true)
    console.log(addStudentForm().instance().state);

      done(); // <- HERE ->
    })


  })