# Automatically make unit tests

If you like hacking Scheme on Emacs and evaling expressions from
buffers (just checking in the REPL to see if things look right), this
little app is great for turning that into (kinda shabby) unit tests in
a `tests/run.scm` file.

So if you have made a procedure called `+` that adds numbers, and you
check it in the REPL by evaling

    (+ 10 2 300)

and you think it looks right, this app'll turn that into a test that
looks like this:

    (unless (equal? 312 (+ 10 2 300))
      (error "(+ 10 2 300)"))

Any pre-existing forms in a pre-existing `tests/run.scm` are kept, and
duplicates across the two files are removed, but comments and such are
lost, so be careful.

Either have a separate file in your source directory (this file does
not need to be checked into VCS) or move things into such a file from
whereever you have them, and then

    make-tests /my/sloppy/old/repl-testing-file.scm

Also put any `import`s and `define`s that are needed to run the tests.

This will create

    /my/sloppy/old/tests/run.scm

Look through it, edit it until you're happy etc. Again, re-running
`make-tests` will clobber any formatting, commenting etc that you do in
there, so be careful.

For source code,

    git clone https://idiomdrottning.org/make-tests