9.9 Grand Regression Test Checking

What is this all about?

Regression tests (usually abbreviated "regtests") is a collection of ‘.ly’ files used to check whether LilyPond is working correctly. Example: before version 2.15.12 breve noteheads had incorrect width, which resulted in collisions with other objects. After the issue was fixed, a small ‘.ly’ file demonstrating the problem was added to the regression tests as a proof that the fix works. If someone will accidentally break breve width again, we will notice this in the output of that regression test.

How can I help?

We ask you to help us by checking one or two regtests from time to time. You don’t need programming skills to do this, not even LilyPond skills - just basic music notation knowledge; checking one regtest takes less than a minute. Simply go here:


Some tips on checking regtests

Description text

The description should be clear even for a music beginner. If there are any special terms used in the description, they all should be explained in our Music Glossary or Internals Reference. Vague descriptions (like "behaves well", "looks reasonable") shouldn’t be used.

LilyPond — Contributor’s Guide v2.19.4 (development-branch).