I got tired of: bash/sh portability issues; writing long, complicated, test
code; weird shell constructs for simple things; constantly putting in
&>/dev/null; and many more.
Sure you can write test scripts in any language, but for the kind of code I write, I have to run lots of shell commands, capture the output, and check that.
Less typing, less output.
Simple examples here.
The test program for 'gitpod' is TAP compliant and can be found here. A syntax colored version is here.
perl 5.10.0 or later, and any posix shell that understands very simple redirection.
The rest of the documentation is here.