Alcotest is a lightweight and colourful test framework.

Alcotest exposes simple interface to perform unit tests. It exposes
a simple TESTABLE module type, a check function to assert test
predicates and a run function to perform a list of unit -> unit
test callbacks.

Alcotest provides a quiet and colorful output where only faulty runs
are fully displayed at the end of the run (with the full logs ready to
inspect), with a simple (yet expressive) query language to select the
tests to run.
