test-lib functions: add --author support to test_commit

Add support for --author to "test_commit". This will simplify some
current and future tests, one of those is being changed here.

Let's also line-wrap the "git commit" command invocation to make diffs
that add subsequent options easier to add, as they'll only need to add
a new option line.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t7509-commit-authorship.sh

@@ -18,11 +18,8 @@ message_body () {
 }
 
 test_expect_success '-C option copies authorship and message' '
-	echo "Initial" >foo &&
-	git add foo &&
-	test_tick &&
-	git commit -m "Initial Commit" --author Frigate\ \<flying@over.world\> &&
-	git tag Initial &&
+	test_commit --author Frigate\ \<flying@over.world\> \
+		"Initial Commit" foo Initial Initial &&
 	echo "Test 1" >>foo &&
 	test_tick &&
 	git commit -a -C Initial &&

t/test-lib-functions.sh

@@ -185,6 +185,8 @@ debug () {
 #	Do not call test_tick before making a commit
 #   --signoff
 #	Invoke "git commit" with --signoff
+#   --author=<author>
+#	Invoke "git commit" with --author=<author>
 #
 # This will commit a file with the given contents and the given commit
 # message, and tag the resulting commit with the given tag name.
@@ -193,6 +195,7 @@ debug () {
 
 test_commit () {
 	notick= &&
+	author= &&
 	signoff= &&
 	indir= &&
 	while test $# != 0
@@ -201,6 +204,10 @@ test_commit () {
 		--notick)
 			notick=yes
 			;;
+		--author)
+			author="$2"
+			shift
+			;;
 		--signoff)
 			signoff="$1"
 			;;
@@ -222,7 +229,9 @@ test_commit () {
 	then
 		test_tick
 	fi &&
-	git ${indir:+ -C "$indir"} commit $signoff -m "$1" &&
+	git ${indir:+ -C "$indir"} commit \
+	    ${author:+ --author "$author"} \
+	    $signoff -m "$1" &&
 	git ${indir:+ -C "$indir"} tag "${4:-$1}"
 }