Testing onChange function in Jest

Question

I\'m relatively new to Jest and testing in general. I have a component with an input element:

import * as React from \"react\";

export interface inputProps{
            


        

Answer 1

I figured out the solution.

So, instead of passing in the value inside InputBox, we have to pass it inside the second param of simulate as shown below. Then we simply check for equality against the first arg of the first call to the mockFn. Also, we can get rid of the event.preventDefault();

it("onChange param is the same value as the input element's value property", () => {
    const mockFn = jest.fn();
    const input = enzyme.shallow();

    input.find('input').simulate('change', {target: {value: 'matched'} });
    expect(mockFn.mock.calls[0][0]).toBe('matched');
});