在Jest和Sinon无法正常工作的情况下进行测试功能调用

Question

I'm trying to assert the number of times my React class method is called after an event. I have tried using sinon.spy and jest.fn() to no avail.

Using sinon.spy:

test('Some test', (done) => {
  const page = renderLookupPage();
  const formInputButton = page.find('.button').first();
  formInputButton.simulate('click');

  let spy = sinon.spy(page.instance().myReactMethod);

  const button = page.find('.tag').first();
  button.simulate('click');

  setTimeout(() => {
        try {
            console.log(spy.callCount); //0
          done();
        } catch (error) {
          done.fail(error);
        }
      }, 100);
    });

with jest.fn():

test('Some test', (done) => {
  const page = renderLookupPage();
  const formInputButton = page.find('.button').first();
  formInputButton.simulate('click');

  page.instance().myReactMethod = jest.fn(() => {});

  const button = page.find('.tag').first();
  button.simulate('click');

      setTimeout(() => {
        try {
            console.log(page.instance().myReactMethod.mock.calls.length); //0
          done();
        } catch (error) {
          done.fail(error);
        }
      }, 100);
    });

I have assurance the method in question is definitely being called. What is more confusing is a console.log statement in the method prints before the

console.log(spy.callCount)

Any pointers in the right direction will be highly appreciated! Cheers!

Answer 1

The solution was simple,

I moved the line

page.instance().myReactMethod = jest.fn(() => {});

above the previous line:

formInputButton.simulate('click');

Not sure why this worked, and it would be great to hear from someone as to why this affected the result?

NOTE: formInputButton doesnt call the function in question