How to test your WordPress theme

How To Test Your WordPress Theme: A Guide to Ensuring Quality

How do you test your WordPress theme? A good question, that can dramatically improve the quality of your WP themes, by implementing simple steps.


When you create a WordPress theme, it’s important to test it thoroughly before releasing it to the public or going live with a client’s website. This ensures that your theme is of high quality and will work properly for its intended audience. In today’s guide, I’ll guide your through the basic steps to test your WordPress theme.

Set up a local development environment

To test your WordPress theme, you should start by setting up a development environment. This can be done easily with for example LocalWP, MAMP or XAMMP. This allows you to work with a local version of your site, which is faster and easier to work with than a live site.

Import test content

Once you’ve set up your development environment, you’ll need to import test content. You can create your own test content, but it’s much easier to use the Theme Unit Test, which includes many different types of content. This will help ensure that your theme works in circumstances you may not have anticipated. You can import the Theme Unit Test using the WordPress Importer.

Test WordPress settings

You should also test your theme with different WordPress settings. For example, you can set the Site Title and Tagline to something long and even longer to test how your theme handles edge cases for site titles and taglines. You can also set “Blog pages show at most” to 5 to ensure that index/archive pagination is triggered. Enable “Threaded Comments” at least 3 levels deep to facilitate testing of your theme’s comment list styling.

Use testing and debugging tools

There are a variety of tools you can use to test and debug your theme. The Theme Check plugin adds a dashboard link under Appearance so you can run the exact same checks that WordPress.org does right from your administration panel. Doing this prior to uploading your theme lets you know what needs to be addressed prior to submission. Running the check will give you a list of any warnings your theme has generated. To see what items are required for the theme to be accepted in the WordPress.org theme directory, as well as any recommended items that may be missing from your theme.

You can also use the Developer plugin to automatically download and install some of the plugins you’ll want when developing your theme, and Debug Bar to organize debug messages in an easy-to-read layout.

Finally, Log Deprecated Notices displays a list of the deprecated function notices in your theme and where the code can be found.

Test in different browsers

A key element in web development. Test your theme in different browsers, or you’ll be in for a surprise! When submitting your theme to WordPress.org, it’s expected that it works well in modern browsers and at any resolution. You should test your theme against several popular browsers before submitting, both mobile and desktop.

Many browsers have built-in features making it easy to test, for example the Chrome Developer Tools, Firefox Developer Tools, and the Microsoft Edge tools. Note that Internet Explorer is no longer supported by WordPress since 5.8 release.

Validate HTML and CSS

Your theme should use valid HTML5 and CSS code. There are a variety of tools that will test your site for valid code. Including the HTML5 validator and the CSS validator.

W3C Markup Validation Service is a free tool provided by the World Wide Web Consortium (W3C) that allows you to check the validity of your HTML5 code.

W3C CSS Validation Service is another free tool provided by the W3C. It allows you to check the validity of your CSS code.

Other popular tools are HTML5 Outliner and CSS Lint. HTML5 Outliner allows you to visualize the structure of your HTML5 document. It can be helpful in identifying any structural issues in your code. CSS Lint checks your CSS code for errors and potential problems.

Final notes

Implementing at least some of these steps can ensure that your WordPress theme is of high quality. This ensures that it works properly for its intended audience. Test your WordPress theme thoroughly to avoid common issues and ensure that your users have a great experience with your theme.