I found Bats straightforward and simple to use, never felt the need to reinvent the wheel there.
1) bloated
2) doesn't use a very nice syntax (hint: bashisms are not a very nice syntax). Compare BATS assertions with this for example (the test of my test library, which uses the library's own functions): https://github.com/pmarreck/tinytestlib/blob/yolo/test Call me crazy but I think `assert_equal "4" "$result"` is a lot more readable than `[ "$result" -eq 4 ]`
3) doesn't let you assert on all of (return code, stdout, stderr) from running a single command. I created a `capture` function to do that and bring those all into named variables that you can then assert on.
But overall I wanted something tiny that you could easily include alongside a bash script instead of establishing as a new dependency you'd have to install separately. Honestly, I feel that functions like assert_equal, assert_not_equal, assert_success, assert_failure, assert_match and assert_no_match (which all raise on failure) should be built into every programming language's standard library.
I know that you can sort of get by just using `set -e` and just do a comparison operation, but...