QA Engineers, Stay Out of Cypress Component Testing, for Your Own Sake!

Human Factors. Developers may do as their wish. But for QA Engineers, just do your black-box testing, and stay out of the developer’s turf.

A repost of my past article published on Medium in 2023.

Update 2023–08–28: Developers, you shouldn’t do Cypress Component Testing either.

I have been hearing Cypress testers, who are unable to do end-to-end testing, started talking about how great Cypress Component Testing is.

Cypress Component Testing, let’s just accept the term that Cypress defines, is mainly for developers.

https://www.cypress.io/blog/2022/12/15/cypress-component-testing-for-developers/

“Cypress currently has official mounting libraries for React, Angular, Vue, and Svelte and support for the following development servers and frameworks: Create React App 4+, Next.js 11+, …” — Cypress Doc

Clearly, Cypress Component Testing is NOT black-box testing (as an end-user), as it is limited to the apps in a certain web framework (even specific versions). At most, it is ‘Gray-box testing’. I have seen some examples on its official doc, but frankly, it is quite complex and messy (You can verify the example script with your end-user or manual tester).

There is a mount task (to include the component code) before testing. Here is an official example:

import Button from './Button'
it('uses custom text for the button label', () => {
 cy.mount(<Button>Click me!</Button>)
 cy.get('button').should('contains.text', 'Click me!')
})

I know the argument for Cypress component testing, “browser-based, allowing you test not only your component’s functionality but also styles and appearance” [doc]. From my 20+ years of experience (in both coding and testing), this has very little value, which I will elaborate in a separate article. For Cypress testers fixated on this, (by the way, Cypress.IO is dying) just think the following simple questions:

• Why it is NOT included in the Testing Pyramid?

• Did your team do end-to-end UI Testing (in the Testing Pyramid) well?

• Every activity comes with a cost. Do you, from the project’s perspective, really think the effort on this kind of component testing is justifiable?

Black and White
By the way, we call “BlackBox” and “WhiteBox” testing for a very good reason, indicating there is a clear gap, no middle ground. But the so-called cypress component testing (if performed by QA engineers) crosses that line.

I might be an old-fashioned software engineer and SET. I think mixing black-box and white-box testing is wrong, very wrong.