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UI Testing Myths

November 08, 2018


Some common myths around testing and what the reality is...

Myth 1: "Tests always break when I make any changes to the code"

This is actually a truth... if the tests are written incorrectly. If your test is testing implementation details, then of course they'll break when the implementation changes! But your user doesn't care about the implementation details. In fact, they don't even care whether you're using React, Angular, or jQuery. So for the most part, your tests shouldn't care about that either. 💯

Unfortunately, many tools out there encourage testing implementation details. Do that and you'll often wind up rewriting tests. "Why am I even testing this!?" you'll ask yourself, and I don't blame you. That's why on TestingJavaScript.com I show you how test the right way.

Myth 2: "I can't test a 'connected' redux component"

The conventional wisdom of testing components that use Redux is that you should test the component in isolation from Redux, and then test the Redux action creators and reducers separately.

But if you do this, your tests can't give you any confidence that your components communicate properly with Redux.

Instead, you can actually test your connected component with your real Redux store. Do this, and you'll get the confidence that your component is rendering properly, and that the Redux action creators and reducers are all working together in tandem. Just like they will in production. ✅

On TestingJavaScript.com, I show you how to test in this way. The same concepts apply for React Router 🔀 and other providers (like the Theme Provider from emotion 👩‍🎤), and the course will show how to apply this method to those, too!

Myth 3: "End-to-End tests are slow and brittle"

This, too, can be true if the tests are written incorrectly. A common mistake I see in E2E testing is doing the same things in every test — for instance, every test going through the whole registration and login flow before doing whatever is needed for the test. When you do stuff like this, you start seeing a lot of duplication, and that's when you start creating things like "page objects" (which is a poor practice). 😐

On TestingJavaScript.com, I show you how you can get confidence that the registration and login flows are working, and then skip those for the rest of your tests so you can significantly speed up the tests and reduce the points of failure. When you write tests this way and use tools like cypress-testing-library, practices like page objects are totally unnecessary, and your tests are easier to maintain, more reliable, and run faster. You might even find yourself replacing Chrome with Cypress as your development workflow tool (which I show you how to do in the course as well!) 😱

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Kent C. Dodds

Kent C. Dodds is a JavaScript software engineer and teacher. He's taught hundreds of thousands of people how to make the world a better place with quality software development tools and practices. He lives with his wife and four kids in Utah.