Research test runners

[grantcodes]

Once a decision has been made on #3 I'd also like to research possibilities for writing and running tests and evaluate them based on their package sizes, runtimes and carbon emissions.

I have a feeling that someone else may have already done much of the work here (especially on speed), but I have no references yet.

[grantcodes]

After a little bit of searching around I found various comparisons, particularly around the speed of various rest runners:

• https://github.com/artemave/node-test-runners-performance-comparison
• https://medium.com/dailyjs/javascript-test-runners-benchmark-3a78d4117b4
• https://betterstack.com/community/guides/testing/best-node-testing-libraries/
• https://medium.com/@lucas_levandoski/node-native-test-runner-benchmark-5cb47d4706cb

Looking at the results of the comparisons, I would expect the built in Node.js test runner to be the best option for sustainability focused testing for a few reasons:

• It appears to be one of the fastest test runners around right now
• Being built into Node.js itself brings some advantages:
  • No need for extra dependency or downloads
  • Support and maintenance should hopefully be good as part of the core language