t3432: distinguish "noop-same" v.s. "work-same" in "same head" tests

Change "same head" introduced in the preceding commit to check whether
the rebase.c code lands in the can_fast_forward() case in, and thus
prints out an "is up to date" and aborts early.

In some of these cases we make it past that and to "rewinding head",
then do a rebase, only to find out there's nothing to change so HEAD
stays at the same OID.

These tests presumed these two cases were the same thing. In terms of
where HEAD ends up they are, but we're not only interested in rebase
semantics, but also whether or not we're needlessly doing work when we
could avoid it entirely.

I'm adding "same" and "diff" here because I'll follow-up and add
--no-ff tests, where some of those will be "diff"-erent, so add the
"diff" code already.

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

t/t3432-rebase-fast-forward.sh

@@ -18,55 +18,72 @@ test_expect_success setup '
 test_rebase_same_head () {
 	status="$1" &&
 	shift &&
-	test_expect_$status "git rebase $* with $changes is no-op" "
+	what="$1" &&
+	shift &&
+	cmp="$1" &&
+	shift &&
+	test_expect_$status "git rebase $* with $changes is $what" "
 		oldhead=\$(git rev-parse HEAD) &&
 		test_when_finished 'git reset --hard \$oldhead' &&
-		git rebase $* &&
+		git rebase $* >stdout &&
+		if test $what = work
+		then
+			test_i18ngrep 'rewinding head' stdout
+		elif test $what = noop
+		then
+			test_i18ngrep 'is up to date' stdout
+		fi &&
 		newhead=\$(git rev-parse HEAD) &&
-		test_cmp_rev \$oldhead \$newhead
+		if test $cmp = same
+		then
+			test_cmp_rev \$oldhead \$newhead
+		elif test $cmp = diff
+		then
+			! test_cmp_rev \$oldhead \$newhead
+		fi
 	"
 }
 
 changes='no changes'
-test_rebase_same_head success
-test_rebase_same_head success master
-test_rebase_same_head success --onto B B
-test_rebase_same_head success --onto B... B
-test_rebase_same_head success --onto master... master
-test_rebase_same_head success --no-fork-point
-test_rebase_same_head success --fork-point master
-test_rebase_same_head failure --fork-point --onto B B
-test_rebase_same_head failure --fork-point --onto B... B
-test_rebase_same_head success --fork-point --onto master... master
+test_rebase_same_head success work same
+test_rebase_same_head success noop same master
+test_rebase_same_head success noop same --onto B B
+test_rebase_same_head success noop same --onto B... B
+test_rebase_same_head success noop same --onto master... master
+test_rebase_same_head success noop same --no-fork-point
+test_rebase_same_head success work same --fork-point master
+test_rebase_same_head failure noop same --fork-point --onto B B
+test_rebase_same_head failure work same --fork-point --onto B... B
+test_rebase_same_head success work same --fork-point --onto master... master
 
-test_expect_success 'add work to side' '
+test_expect_success 'add work same to side' '
 	test_commit E
 '
 
 changes='our changes'
-test_rebase_same_head success
-test_rebase_same_head success master
-test_rebase_same_head success --onto B B
-test_rebase_same_head success --onto B... B
-test_rebase_same_head success --onto master... master
-test_rebase_same_head success --no-fork-point
-test_rebase_same_head success --fork-point master
-test_rebase_same_head failure --fork-point --onto B B
-test_rebase_same_head failure --fork-point --onto B... B
-test_rebase_same_head success --fork-point --onto master... master
+test_rebase_same_head success work same
+test_rebase_same_head success noop same master
+test_rebase_same_head success noop same --onto B B
+test_rebase_same_head success noop same --onto B... B
+test_rebase_same_head success noop same --onto master... master
+test_rebase_same_head success noop same --no-fork-point
+test_rebase_same_head success work same --fork-point master
+test_rebase_same_head failure work same --fork-point --onto B B
+test_rebase_same_head failure work same --fork-point --onto B... B
+test_rebase_same_head success work same --fork-point --onto master... master
 
-test_expect_success 'add work to upstream' '
+test_expect_success 'add work same to upstream' '
 	git checkout master &&
 	test_commit F &&
 	git checkout side
 '
 
 changes='our and their changes'
-test_rebase_same_head success --onto B B
-test_rebase_same_head success --onto B... B
-test_rebase_same_head failure --onto master... master
-test_rebase_same_head failure --fork-point --onto B B
-test_rebase_same_head failure --fork-point --onto B... B
-test_rebase_same_head failure --fork-point --onto master... master
+test_rebase_same_head success noop same --onto B B
+test_rebase_same_head success noop same --onto B... B
+test_rebase_same_head failure work same --onto master... master
+test_rebase_same_head failure work same --fork-point --onto B B
+test_rebase_same_head failure work same --fork-point --onto B... B
+test_rebase_same_head failure work same --fork-point --onto master... master
 
 test_done