Mocking window object with Jest

Photo by Michael Jasmund on Unsplash

Another unit test and another mocking issue. The code to be tested is more less like this:

To test this component we need to mock:

window.location.pathname

Static mocking if we need only one value:

Dynamic pathname mocking if we need the value to be changed during the test:

window.open

window.location.replace

Testing

First testing the pathname check — new window should be opened when specific path is within window.location.pathname:

And the replacement of location:

The code

All the code can be find in this article’s repository: https://github.com/marekrozmus/blog-mocking-window-object-with-jest

Check also my other posts about unit testing:

• Mocking setTimeout with Jest.
• When to use mockClear, mockReset and mockRestore with mock and spyOn.