Because Quality is Key!
Just a simple example that testing software is mostly a question of will.
Uses GNU Make to check and package GNU BASH based scripts.
Use make lint to run ShellCheck on all scripts.
Use make test to run all test suites with basic Test Anything Protocol support.
Use VERBOSE=TRUE make test to always see test outputs
Use make ci on a continuous integration pipeline to run both lint and test
Use make package to create a distribution package, including source
Use make help to get info on what can be run for which purpose