The test comparison shows all of the changes that occurred between
the current release and the prior release. Each test that has a
-significant difference in output is displayed, with the old
-version on the left and the new version on the right.
+significant (noticeable) difference in output is displayed, with
+the old version on the left and the new version on the right.
+
+Some of the small changes can be ignored (slightly different slur
+shapes, small variations in note spacing), but this is not always
+the case: sometimes even the smallest change means that something
+is wrong. To help in distinguishing these cases, we use bigger
+staff size when small differences matter.
+
+Staff size 30 generally means "pay extra attention to details".
+Staff size 40 (two times bigger than default size) or more means
+that the regtest @strong{is} about the details.
+
+Staff size smaller than default doesn't mean anything.
Regression tests whose output is the same for both versions are
not shown in the test comparison.
@node Regtest comparison
@section Regtest comparison
-Before modified code is committed to master, a regression test
+Before modified code is committed to @code{master} (via @code{staging}),
+a regression test
comparison must be completed to ensure that the changes have
not caused problems with previously working code. The comparison
is made automatically upon compiling the regression test suite
@item
Before making changes to the code, establish a baseline for the comparison by
-going to the @file{lilypond-git/build/} directory and running:
+going to the @file{$LILYPOND_GIT/build/} directory and running:
@example
make test-baseline
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.
-We are asking you to help us by checking a regtest or two from time to time.
+@subheading 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:
@example
-@uref{http://www.holmessoft.co.uk/homepage/private/regtests/}
+@uref{http://www.philholmes.net/lilypond/regtests/}
@end example
@subheading Some tips on checking regtests
Vague descriptions (like "behaves well", "looks reasonable") shouldn't be used.
@ignore
+this may be useful for advanced regtest checking
@subsubheading Is regtest straightforward and systematic?
Unfortunately some regtests are written poorly. A good regtest should be