Enhance e2e testing by adding stdout and stderr checks, and normalizing input lists

[scyyx5]

No description provided.

[toastwaffle]

Have you tested this?

I'm thinking this repo should actually contain some e2e tests for testing the e2e test framework (which is a lovely bootstrapping problem). @chrisnovakovic do you have any thoughts on that?

[scyyx5]

I confirmed exit code by e.g.:

bash -c '(false) > >(tee /tmp/stdout.log) 2> >(tee [stderr.log](http://_vscodecontentref_/2) >&2); status=$?; echo status=$status' ()

Do you want me to add other test?