pickaxe tests: add test for diffgrep_consume() internals
In diffgrep_consume() we generate a diff, and then advance past the
"+" or "-" at the start of the line for matching. This has been done
ever since the code was added in
f506b8e8b5f (git log/diff: add
-G<regexp> that greps in the patch text, 2010-08-23).
If we match "line" instead of "line + 1" no tests fail, i.e. we've got
zero coverage for whether any of our searches match the beginning of
the line or not. Let's add a test for this.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>