Clarification for Testing Environment Variables

[ryanhaticus]

Documentation / Examples

• Make sure the linting passes by running pnpm lint
• The examples guidelines are followed from our contributing doc

The Issue

When it came to testing environment variables with jest in the current release of NextJS, I ran into an issue where my variables were seemingly undefined for no reason. With some research and the help from a friend in discussion post #38353 it was determined further configuration steps were needed in relation to the environment variables for jest. At the time being, no direct link is made between Setting up Jest and Test Environment Variables.

The Change

This fix provides further clarification on the issue by creating a new link within the note on the Setting up Jest page. Moreover, further explanations were added to ensure developers understand the test environment is completely separate from both development and production meaning files like .env.development and env.prodution won't be recognized when testing.

Supporting Documentation

This is an issue time and time again for developers. Not only have I experienced this, but others have asked on both GitHub Discussions and StackOverflow. Moreover, many of the solutions from 2020 no longer work properly.

I hope this is sufficient enough for a contribution to the documentation. Minor improvements like these create the ideal developer experience Next.js is known for. :)

[ryanhaticus]

These changes look good. The concise wording is better!

Green light from me!