Google Tag Manager now lets you add unit tests directly to your custom templates. This is useful, since it allows you to control the code stability of your templates, especially if you've decided to share those templates with the public. I recently shared a general guide for how template tests work, but I wanted to expand the topic a little, and share with you two walkthroughs of custom template tests: one for a variable template and one for a tag template.
Google Tag Manager introduced the capability to add tests to your Custom Templates. Tests, in this context, refer specifically to unit tests that you write in order to make sure your template code works in a predictable way. Unit tests are also used to drive development, ensuring that you have added contingencies for all the different scenarios that the template, when coupled with user input, might introduce. In this guide, I'll introduce how the Tests feature works.
One of the biggest fears I have as a Google Tag Manager user is a broken release of the website (or app) on which I have deployed GTM. Far too often, lack of proper communication practices within an organization lead to a release being pushed out without thoroughly testing how this release impacts any existing tracking solutions. Luckily there are ways to mitigate this. The most significant and impactful precautions you can take are all about process: