And here's the test, patterned after test_rebase_preserves_logmsg,
plus one that checks the order of the "from:", "via:", "date:", and
"orig:" headers in the output of got log (after my earlier mistake).

As individual commits (on top of the others) at:
https://gotweb.khjk.org/?action=summary&headref=authortime-test&path=got.git

-p

PS: I used "orig:" for the author time header because I could not think
of something bettat that would still line up with the "date" above it,
and having the two dates not line up seemed egregious.


diff /home/pesco/work/got
commit - 9a2e7ad4870891a7244450ed93be14d82bbd104b
path + /home/pesco/work/got
blob - aa8c37ce5f9af6c3b3fdf320c95dd8316334d667
file + regress/cmdline/rebase.sh
--- regress/cmdline/rebase.sh
+++ regress/cmdline/rebase.sh
@@ -1002,6 +1002,115 @@ test_rebase_preserves_logmsg() {
 	test_done "$testroot" "$ret"
 }
 
+test_rebase_preserves_author_time() {
+	local testroot=`test_init rebase_preserves_author_time`
+
+	git -C $testroot/repo checkout -q -b newbranch
+	echo "modified delta on branch" > $testroot/repo/gamma/delta
+	git_commit $testroot/repo -m "modified delta on newbranch"
+
+	sleep 1		# get a new timestamp
+	echo "modified alpha on branch" > $testroot/repo/alpha
+	git_commit $testroot/repo -m "modified alpha on newbranch"
+
+	(cd $testroot/repo && got log -c newbranch -l2 | \
+		egrep '^(commit|date:)' > $testroot/dates.expected)
+
+	local orig_commit1=`git_show_parent_commit $testroot/repo`
+	local orig_commit2=`git_show_head $testroot/repo`
+
+	git -C $testroot/repo checkout -q master
+	echo "modified zeta on master" > $testroot/repo/epsilon/zeta
+	git_commit $testroot/repo -m "committing to zeta on master"
+	local master_commit=`git_show_head $testroot/repo`
+
+	got checkout $testroot/repo $testroot/wt > /dev/null
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		test_done "$testroot" "$ret"
+		return 1
+	fi
+
+	sleep 1		# get a new timestamp
+	(cd $testroot/wt && got rebase newbranch > /dev/null \
+		2> $testroot/stderr)
+
+	git -C $testroot/repo checkout -q newbranch
+	local new_commit1=`git_show_parent_commit $testroot/repo`
n+	local new_commit2=`git_show_head $testroot/repo`
+
+	echo -n > $testroot/stderr.expected
+	cmp -s $testroot/stderr.expected $testroot/stderr
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		diff -u $testroot/stderr.expected $testroot/stderr
+		test_done "$testroot" "$ret"
+		return 1
+	fi
+
+	(cd $testroot/wt && got log -c newbranch -l2 | \
+		egrep '^(commit|orig:)' > $testroot/dates)
+	ed -s $testroot/dates.expected <<-EOF
+	,s/$orig_commit1/$new_commit1/
+	,s/$orig_commit2/$new_commit2/
+	,s/^date:/orig:/
+	w
+	EOF
+	cmp -s $testroot/dates.expected $testroot/dates
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		diff -u $testroot/dates.expected $testroot/dates
+	fi
+
+	test_done "$testroot" "$ret"
+}
+
+test_rebase_header_order() {
+	local testroot=`test_init rebase_header_order`
+	local committer="Flan Luck <flan_luck@openbsd.org>"
+
+	git -C $testroot/repo checkout -q -b newbranch
+	echo "modified delta on branch" > $testroot/repo/gamma/delta
+	git_commit $testroot/repo -m "modified delta on newbranch"
+
+	git -C $testroot/repo checkout -q master
+	echo "modified zeta on master" > $testroot/repo/epsilon/zeta
+	git_commit $testroot/repo -m "committing to zeta on master"
+	local master_commit=`git_show_head $testroot/repo`
+
+	got checkout $testroot/repo $testroot/wt > /dev/null
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		test_done "$testroot" "$ret"
+		return 1
+	fi
+
+	sleep 1		# get a new timestamp
+	(cd $testroot/wt && env GOT_AUTHOR="$committer" got rebase newbranch \
+		> /dev/null 2> $testroot/stderr)
+
+	echo -n > $testroot/stderr.expected
+	cmp -s $testroot/stderr.expected $testroot/stderr
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		diff -u $testroot/stderr.expected $testroot/stderr
+		test_done "$testroot" "$ret"
+		return 1
+	fi
+
+	echo "from:\nvia:\ndate:\norig:" > $testroot/headers.expected
+	(cd $testroot/wt && got log -c newbranch -l1 | \
+		egrep '^(from:|via:|date:|orig:)' | sed -e 's/: .*/:/' \
+		> $testroot/headers)
+	cmp -s $testroot/headers.expected $testroot/headers
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		diff -u $testroot/headers.expected $testroot/headers
+	fi
+
+	test_done "$testroot" "$ret"
+}
+
 test_rebase_no_commits_to_rebase() {
 	local testroot=`test_init rebase_no_commits_to_rebase`
 
@@ -2286,6 +2395,8 @@ run_test test_rebase_no_op_change
 run_test test_rebase_in_progress
 run_test test_rebase_path_prefix
 run_test test_rebase_preserves_logmsg
+run_test test_rebase_preserves_author_time
+run_test test_rebase_header_order
 run_test test_rebase_no_commits_to_rebase
 run_test test_rebase_forward
 run_test test_rebase_forward_path_prefix