Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

Clojure: Expectations Warn On State Change During Test Runs

DZone's Guide to

Clojure: Expectations Warn On State Change During Test Runs

· Java Zone
Free Resource

Learn how to troubleshoot and diagnose some of the most common performance issues in Java today. Brought to you in partnership with AppDynamics.

 While writing tests it can be easy to accidentally change any global state that exists in your application. I've previously written about Redefining State Within a Test; however, redef-state and with-redefs only help you if you redefine all of the affected state. The situation is even more problematic due to the fact that accidental state alteration often doesn't cause issues until a completely unrelated test suddenly fails. After being bitten by this issue a few times, I added (to expectations) the ability to warn when global state is modified by a test.

As of version 1.4.24 if you add (expectations/warn-on-iref-updates) anywhere, then expectations will provide you with a warning whenever any global state is altered.

While you can add that snippet anywhere, I prefer to add it to the expectations Before Run Hook. There's an example expectations_options.clj in the expectations codebase that shows all of the code you need to enable this feature. Simply add this file or add the function to your existing file and you should see a warning on any global state alteration. If you're not sure where to put this file, refer to the Before Run Hook blog post.

Here's an example warning (generated by running the expectations tests).

WARNING: success.success-examples:280 modified #'success.success-examples-src/an-atom from "atom" to "another atom"
The warning should let you know which test is doing an unexpected modification, and the to and from values should give you an idea of where in the source the alteration is occurring.

Understand the needs and benefits around implementing the right monitoring solution for a growing containerized market. Brought to you in partnership with AppDynamics.

Topics:

Published at DZone with permission of Jay Fields, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}