Missing tests (build-time tests and DEP-8)

[Miriam España Acebal]

This package includes a ruby-based test suite as can be seen in /check/README.md, but it is disabled by now.

I gave it a try with no luck (maybe that's why they are skipped in Debian):

Finished in 122.186977495 seconds.
-------------------------------------------------------------------------------
244 tests, 247 assertions, 215 failures, 0 errors, 19 pendings, 0 omissions, 0 notifications
11.8852% passed
-------------------------------------------------------------------------------
2.00 tests/s, 2.02 assertions/s
FAIL: check-help.sh
FORM 5.0 (Aug 1 2024)
  0.053333 form units in 4.537 seconds (cpu time)
  corresponding to 42.31 form units per hour
PASS: benchmark-fu.sh
==========================================================
1 of 2 tests failed