What is the process to ensure the Bootstrapper object of the window is accessible for unit testing?

Question

What is the process to ensure the Bootstrapper object of the window is accessible for unit testing?

Within my project, there is a function that calls a method from the bootstrapper object within the window. Here's the code for the function:

export default function measurement(analObj) {
    if (window.Bootsrapper._trackAnalytics === function) {
        window.Bootstrapper._trackAnalytics(analObj);
    }
}

To test this function in Jest, I wrote the following code snippet:

import measurement from "../helpers/measurement";

describe('Test measurement', () => {
  beforeAll(() => {
    const Bootstrapper = {
      _trackAnalytics: function(obj) {
        return obj;
      },
    };
    window.Bootstrapper = Bootstrapper;
  })
  test('should send analytics object to rtrack analyitics', () => {
    const testObj = {
      pageName: "Leave Abasence"
    }
    const result = measurement(testObj);
    expect(testObj).toEqual(result);
  })
})

When running the test, the variable "result" returns "undefined" as I am facing issues with making the

window.measurement._trackAnalytics

function available during runtime.

I have a couple of questions:

Is my approach to unit testing this scenario correct? If yes, how can I ensure the availability of the _trackAnalytics function for the measurement function during runtime?
If you have any better suggestions or alternative approaches, please feel free to share.

javascript unit-testing express jestjs

Answer 1

Answer №1

When running your test, the

window.measurement._trackAnalytics

function must be available within the measurement function. Otherwise, you will encounter a TypeError since you are attempting to call something that is not a function.

The issue lies in the fact that the measurement method does not return anything. Despite calling the _trackAnalytics method, no result is returned, leading to an undefined output for result.

To verify that it is indeed being called, consider using a jest mock function. An example test scenario would be:

test('should send analytics object to track analytics', () => {
    const testObj = {
        pageName: 'Leave Absence'
    };

    measurement(testObj);
    expect(window.Bootstrapper._trackAnalytics).toHaveBeenCalledTimes(1);
    expect(window.Bootstrapper._trackAnalytics).toHaveBeenCalledWith(testObj);
});

It's worth noting that there are some errors in your code (presumably typos). In the if condition, you are checking for Bootsrapper instead of Bootstrapper. Additionally, you are verifying equality to function instead of utilizing typeof. The corrected line should appear as follows:

if (typeof window.Bootstrapper._trackAnalytics === 'function') {

Answer 2

When running your test, the

window.measurement._trackAnalytics

function must be available within the measurement function. Otherwise, you will encounter a TypeError since you are attempting to call something that is not a function.

The issue lies in the fact that the measurement method does not return anything. Despite calling the _trackAnalytics method, no result is returned, leading to an undefined output for result.

To verify that it is indeed being called, consider using a jest mock function. An example test scenario would be:

test('should send analytics object to track analytics', () => {
    const testObj = {
        pageName: 'Leave Absence'
    };

    measurement(testObj);
    expect(window.Bootstrapper._trackAnalytics).toHaveBeenCalledTimes(1);
    expect(window.Bootstrapper._trackAnalytics).toHaveBeenCalledWith(testObj);
});

It's worth noting that there are some errors in your code (presumably typos). In the if condition, you are checking for Bootsrapper instead of Bootstrapper. Additionally, you are verifying equality to function instead of utilizing typeof. The corrected line should appear as follows:

if (typeof window.Bootstrapper._trackAnalytics === 'function') {

What is the process to ensure the Bootstrapper object of the window is accessible for unit testing?

Answer №1

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