Why isn't my Jest spy showing as called when I can see that it is?












1














I am trying to determine why exactly my Jest spy isn't being called when I can see that the spy is properly "injected" into my component? Here's my very simple example:



TestComponent.js



export default class TestComponent extends Component {
constructor(props) {
super(props);

this.handleSubmit = this.handleSubmit.bind(this);
}

handleSubmit(event) {
event && event.preventDefault();
console.log("handleSubmit called!");
}

render() {
return (
<form onSubmit={this.handleSubmit}>
<button className="submit-button" type="submit">
Submit
</button>
</form>
);
}
}


TestComponent.test.js



describe("TestComponent tests", () => {
it("`handleSubmit` is called when form is submitted", () => {
const wrapper = shallow(<TestComponent />);
const spy = jest.spyOn(wrapper.instance(), "handleSubmit");

wrapper.find("form").simulate("submit");

expect(spy).toHaveBeenCalled();
});
});


If I do a console.log on the wrapper.instance().handleSubmit I can clearly see that the spy has been injected into the object's property, yet my test still fails stating that the spy was not called.



A CodeSandbox with a working example can be found here: https://codesandbox.io/s/3ymkp3w5x1



Thanks!










share|improve this question
























  • I'm guessing this is due to the fact that the onSubmit function is somehow getting called asynchronously -- going to do some more research in this area.
    – slashp
    Nov 20 '18 at 21:54
















1














I am trying to determine why exactly my Jest spy isn't being called when I can see that the spy is properly "injected" into my component? Here's my very simple example:



TestComponent.js



export default class TestComponent extends Component {
constructor(props) {
super(props);

this.handleSubmit = this.handleSubmit.bind(this);
}

handleSubmit(event) {
event && event.preventDefault();
console.log("handleSubmit called!");
}

render() {
return (
<form onSubmit={this.handleSubmit}>
<button className="submit-button" type="submit">
Submit
</button>
</form>
);
}
}


TestComponent.test.js



describe("TestComponent tests", () => {
it("`handleSubmit` is called when form is submitted", () => {
const wrapper = shallow(<TestComponent />);
const spy = jest.spyOn(wrapper.instance(), "handleSubmit");

wrapper.find("form").simulate("submit");

expect(spy).toHaveBeenCalled();
});
});


If I do a console.log on the wrapper.instance().handleSubmit I can clearly see that the spy has been injected into the object's property, yet my test still fails stating that the spy was not called.



A CodeSandbox with a working example can be found here: https://codesandbox.io/s/3ymkp3w5x1



Thanks!










share|improve this question
























  • I'm guessing this is due to the fact that the onSubmit function is somehow getting called asynchronously -- going to do some more research in this area.
    – slashp
    Nov 20 '18 at 21:54














1












1








1







I am trying to determine why exactly my Jest spy isn't being called when I can see that the spy is properly "injected" into my component? Here's my very simple example:



TestComponent.js



export default class TestComponent extends Component {
constructor(props) {
super(props);

this.handleSubmit = this.handleSubmit.bind(this);
}

handleSubmit(event) {
event && event.preventDefault();
console.log("handleSubmit called!");
}

render() {
return (
<form onSubmit={this.handleSubmit}>
<button className="submit-button" type="submit">
Submit
</button>
</form>
);
}
}


TestComponent.test.js



describe("TestComponent tests", () => {
it("`handleSubmit` is called when form is submitted", () => {
const wrapper = shallow(<TestComponent />);
const spy = jest.spyOn(wrapper.instance(), "handleSubmit");

wrapper.find("form").simulate("submit");

expect(spy).toHaveBeenCalled();
});
});


If I do a console.log on the wrapper.instance().handleSubmit I can clearly see that the spy has been injected into the object's property, yet my test still fails stating that the spy was not called.



A CodeSandbox with a working example can be found here: https://codesandbox.io/s/3ymkp3w5x1



Thanks!










share|improve this question















I am trying to determine why exactly my Jest spy isn't being called when I can see that the spy is properly "injected" into my component? Here's my very simple example:



TestComponent.js



export default class TestComponent extends Component {
constructor(props) {
super(props);

this.handleSubmit = this.handleSubmit.bind(this);
}

handleSubmit(event) {
event && event.preventDefault();
console.log("handleSubmit called!");
}

render() {
return (
<form onSubmit={this.handleSubmit}>
<button className="submit-button" type="submit">
Submit
</button>
</form>
);
}
}


TestComponent.test.js



describe("TestComponent tests", () => {
it("`handleSubmit` is called when form is submitted", () => {
const wrapper = shallow(<TestComponent />);
const spy = jest.spyOn(wrapper.instance(), "handleSubmit");

wrapper.find("form").simulate("submit");

expect(spy).toHaveBeenCalled();
});
});


If I do a console.log on the wrapper.instance().handleSubmit I can clearly see that the spy has been injected into the object's property, yet my test still fails stating that the spy was not called.



A CodeSandbox with a working example can be found here: https://codesandbox.io/s/3ymkp3w5x1



Thanks!







jestjs enzyme






share|improve this question















share|improve this question













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edited Nov 20 '18 at 21:19









skyboyer

3,33611128




3,33611128










asked Nov 20 '18 at 20:21









slashp

1,70212139




1,70212139












  • I'm guessing this is due to the fact that the onSubmit function is somehow getting called asynchronously -- going to do some more research in this area.
    – slashp
    Nov 20 '18 at 21:54


















  • I'm guessing this is due to the fact that the onSubmit function is somehow getting called asynchronously -- going to do some more research in this area.
    – slashp
    Nov 20 '18 at 21:54
















I'm guessing this is due to the fact that the onSubmit function is somehow getting called asynchronously -- going to do some more research in this area.
– slashp
Nov 20 '18 at 21:54




I'm guessing this is due to the fact that the onSubmit function is somehow getting called asynchronously -- going to do some more research in this area.
– slashp
Nov 20 '18 at 21:54












1 Answer
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oldest

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0














Best practice is not to test that handleSubmit was called, but just to check for the results of calling handleSubmit. Having said that...





Issue



onSubmit is bound directly to the value of this.handleSubmit at the time the component renders.





Solution



Use a lambda function (note, this might cause performance issues) so that onSubmit calls the current value of this.handleSubmit when it is invoked:



<form onSubmit={() => this.handleSubmit()}>





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    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    0














    Best practice is not to test that handleSubmit was called, but just to check for the results of calling handleSubmit. Having said that...





    Issue



    onSubmit is bound directly to the value of this.handleSubmit at the time the component renders.





    Solution



    Use a lambda function (note, this might cause performance issues) so that onSubmit calls the current value of this.handleSubmit when it is invoked:



    <form onSubmit={() => this.handleSubmit()}>





    share|improve this answer


























      0














      Best practice is not to test that handleSubmit was called, but just to check for the results of calling handleSubmit. Having said that...





      Issue



      onSubmit is bound directly to the value of this.handleSubmit at the time the component renders.





      Solution



      Use a lambda function (note, this might cause performance issues) so that onSubmit calls the current value of this.handleSubmit when it is invoked:



      <form onSubmit={() => this.handleSubmit()}>





      share|improve this answer
























        0












        0








        0






        Best practice is not to test that handleSubmit was called, but just to check for the results of calling handleSubmit. Having said that...





        Issue



        onSubmit is bound directly to the value of this.handleSubmit at the time the component renders.





        Solution



        Use a lambda function (note, this might cause performance issues) so that onSubmit calls the current value of this.handleSubmit when it is invoked:



        <form onSubmit={() => this.handleSubmit()}>





        share|improve this answer












        Best practice is not to test that handleSubmit was called, but just to check for the results of calling handleSubmit. Having said that...





        Issue



        onSubmit is bound directly to the value of this.handleSubmit at the time the component renders.





        Solution



        Use a lambda function (note, this might cause performance issues) so that onSubmit calls the current value of this.handleSubmit when it is invoked:



        <form onSubmit={() => this.handleSubmit()}>






        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 22 '18 at 3:33









        brian-lives-outdoors

        4,850322




        4,850322






























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