selenium - Why should I ever use CSS selectors as opposed to XPath for automated testing?

Question

Please help me understand why using CSS selectors are even an option for automated testing. I've been using the tool Ghost Inspector some in my workplace for creating lots of automated tests for our stuff. This tool gives you the option of using CSS selectors intead of XPath. Why?

XPath is SO much more durable than CSS. The CSS on any given UI is subject to change almost weekly on some projects/features. This make the tests extremely brittle and prone to being broken regularly.

Is it because most new test writers don't want to learn about anything XPath and wish to stick to the basics? CSS selectors look prettier than XPath syntax? Please convince me. thanks.

Answer 1

JeffC's answer here does plenty to sum up the pros and cons of each locator strategy. But I'll address your points specifically.

First off, there is no need for anyone to convince you that selectors are better, because from a purely functional standpoint, they simply aren't (and I'm saying this as someone with a gold css-selectors tag badge and almost 1000 answers to questions with that tag, so you know I'm not biased). If you're more comfortable with XPath, use it — in terms of features and what you can do, XPath is vastly superior, there really is no contest there. And, as you correctly state, performance is no longer an issue (if it ever was).

Selectors are there for quick and simple use cases and for users coming from HTML and CSS codebases, such as web developers, who want to get started with automated tests without having to learn another DSL. If you're responsible for the CSS of your own site you can also easily copy selectors from your stylesheet into your tests depending on what exactly you're testing.

If on the other hand you're coming from an XML/XSLT/XPath background, wonderful, you get to keep using the XPath you know and love¹!

Yes, Xpath is way more durable than CSS because it can invoke specific content contains functionality.

Having a content contains feature doesn't make XPath more "durable" — it makes it more versatile. If you rely solely on an element's content and that content can potentially change or move around, your XPath becomes no less brittle than a selector that relies solely on an element's attributes or its position in the DOM tree.

You can do any of a number of things to make your XPath or selector more or less brittle, but that's an indicator of how versatile the DSL is, not how brittle it inherently is.

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¹ _{Depending on what version of XPath you're used to.}