react component mock method not called

[bchenSyd]

everything is latest

    "jest": "^21.1.0",
    "react": "^16.0.0",
    "react-dom": "^16.0.0"
    "react-test-renderer": "^16.0.0",
    "enzyme": "^3.1.0",
    "enzyme-adapter-react-16": "^1.0.1",

I have a component and a test like below

//component
class ToggleCheckbox  extends Component{
   onChange=()=>{}
   render(){
      return <div> <button onClick={this.onChange} >click</button> </div> 
   }
}

//test
  it('spy', () => {
    //arrange
    const spy = jest.fn().mockImplementation( ()=>{
      console.log(`spy called`);
    })
    const wrapper = shallow(<ToggleCheckbox />);   
    wrapper.instance().onChange = spy
    wrapper.update(); //Forces a re-render.
    //act
    // wrapper.instance().onChange()
    wrapper.find('button').simulate('click');

    //assert
    expect(spy).toBeCalled(); // this will fail but I don't know why;
  });

the assertion will fail but I don't know why.

I know i'm testing jest , or enzyme here rather than testing my code -- as we are doing shallow and no event gets fired in the test; but I want to know what is going on under the hood;
thanks

[bchenSyd]

I actually tried the mount cases well. it didn't work either

[cpojer]

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[bchenSyd]

hi chris,
would you mind to have a look at the test in my questoin? it's quite a basic one and won't take you more than 5 minutes that I can guarantee . it's quite a common test case but I can't find an answer from google.
thanks

[bchenSyd]

enzymejs/enzyme#944

[bchenSyd]

wrapper.setProps({ term: '36' });
Garath

[github-actions]

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