describing regression checking more explicitely

diff --git a/Documentation/contributor/regressions.itexi b/Documentation/contributor/regressions.itexi
index 3ec39d49cf201b83e7beaaa516a7e4bff66bf28d..45ccbaf7601351007387766861e2a53d49051e5d 100644 (file)
--- a/Documentation/contributor/regressions.itexi
+++ b/Documentation/contributor/regressions.itexi
@@ -188,8 +188,11 @@ twice.
 @enumerate
 
 @item
-Before making changes, a baseline should be established by
-running:
+Run @code{make} with current git master without any of your changes.
+
+@item
+Before making changes to the code, establish a baseline for the comparison by
+going to the @file{lilypond-git/build/} directory and running:
 
 @example
 make test-baseline
@@ -209,7 +212,7 @@ make check
 @end example
 
 After this has finished, a regression test comparison will be
-available at:
+available (relative to the current @file{build/} directory) at:
 
 @example
 out/test-results/index.html
@@ -264,6 +267,15 @@ automatic regression comparison again.
 
 @end enumerate
 
+@advanced{
+Once a test baseline has been established, there is no need to run it again
+unless git master changed. In other words, if you work with several branches
+and want to do regtests comparison for all of them, you can
+@code{make test-baseline} with git master, checkout some branch,
+@code{make} and @code{make check} it, then switch to another branch,
+@code{make} and @code{make check} it without doing @code{make test-baseline}
+again.}
+
 
 @node Finding the cause of a regression
 @section Finding the cause of a regression