Add an expensive test for git-notes

git-notes have the potential of being pretty expensive, so test with
a lot of commits.  A lot.  So to make things cheaper, you have to
opt-in explicitely, by setting the environment variable
GIT_NOTES_TIMING_TESTS.

This patch has been improved by the following contributions:
- Junio C Hamano: tests: fix "export var=val"

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t3302-notes-index-expensive.sh b/t/t3302-notes-index-expensive.sh
new file mode 100755 (executable)
index 0000000..0ef3e95
--- /dev/null
+++ b/t/t3302-notes-index-expensive.sh
@@ -0,0 +1,98 @@
+#!/bin/sh
+#
+# Copyright (c) 2007 Johannes E. Schindelin
+#
+
+test_description='Test commit notes index (expensive!)'
+
+. ./test-lib.sh
+
+test -z "$GIT_NOTES_TIMING_TESTS" && {
+       say Skipping timing tests
+       test_done
+       exit
+}
+
+create_repo () {
+       number_of_commits=$1
+       nr=0
+       parent=
+       test -d .git || {
+       git init &&
+       tree=$(git write-tree) &&
+       while [ $nr -lt $number_of_commits ]; do
+               test_tick &&
+               commit=$(echo $nr | git commit-tree $tree $parent) ||
+                       return
+               parent="-p $commit"
+               nr=$(($nr+1))
+       done &&
+       git update-ref refs/heads/master $commit &&
+       {
+               GIT_INDEX_FILE=.git/temp; export GIT_INDEX_FILE;
+               git rev-list HEAD | cat -n | sed "s/^[  ][      ]*/ /g" |
+               while read nr sha1; do
+                       blob=$(echo note $nr | git hash-object -w --stdin) &&
+                       echo $sha1 | sed "s/^/0644 $blob 0      /"
+               done | git update-index --index-info &&
+               tree=$(git write-tree) &&
+               test_tick &&
+               commit=$(echo notes | git commit-tree $tree) &&
+               git update-ref refs/notes/commits $commit
+       } &&
+       git config core.notesRef refs/notes/commits
+       }
+}
+
+test_notes () {
+       count=$1 &&
+       git config core.notesRef refs/notes/commits &&
+       git log | grep "^    " > output &&
+       i=1 &&
+       while [ $i -le $count ]; do
+               echo "    $(($count-$i))" &&
+               echo "    note $i" &&
+               i=$(($i+1));
+       done > expect &&
+       git diff expect output
+}
+
+cat > time_notes << \EOF
+       mode=$1
+       i=1
+       while [ $i -lt $2 ]; do
+               case $1 in
+               no-notes)
+                       GIT_NOTES_REF=non-existing; export GIT_NOTES_REF
+               ;;
+               notes)
+                       unset GIT_NOTES_REF
+               ;;
+               esac
+               git log >/dev/null
+               i=$(($i+1))
+       done
+EOF
+
+time_notes () {
+       for mode in no-notes notes
+       do
+               echo $mode
+               /usr/bin/time sh ../time_notes $mode $1
+       done
+}
+
+for count in 10 100 1000 10000; do
+
+       mkdir $count
+       (cd $count;
+
+       test_expect_success "setup $count" "create_repo $count"
+
+       test_expect_success 'notes work' "test_notes $count"
+
+       test_expect_success 'notes timing' "time_notes 100"
+       )
+done
+
+test_done