1 files changed, 92 insertions, 0 deletions
diff --git a/t/t4038-diff-combined.sh b/t/t4038-diff-combined.sh
new file mode 100755
index 0000000000..40277c77aa
--- /dev/null
+++ b/t/t4038-diff-combined.sh
@@ -0,0 +1,92 @@
+#!/bin/sh
+
+test_description='combined diff'
+
+. ./test-lib.sh
+
+setup_helper () {
+	one=$1 branch=$2 side=$3 &&
+
+	git branch $side $branch &&
+	for l in $one two three fyra
+	do
+		echo $l
+	done >file &&
+	git add file &&
+	test_tick &&
+	git commit -m $branch &&
+	git checkout $side &&
+	for l in $one two three quatro
+	do
+		echo $l
+	done >file &&
+	git add file &&
+	test_tick &&
+	git commit -m $side &&
+	test_must_fail git merge $branch &&
+	for l in $one three four
+	do
+		echo $l
+	done >file &&
+	git add file &&
+	test_tick &&
+	git commit -m "merge $branch into $side"
+}
+
+verify_helper () {
+	it=$1 &&
+
+	# Ignore lines that were removed only from the other parent
+	sed -e '
+		1,/^@@@/d
+		/^ -/d
+		s/^\(.\)./\1/
+	' "$it" >"$it.actual.1" &&
+	sed -e '
+		1,/^@@@/d
+		/^- /d
+		s/^.\(.\)/\1/
+	' "$it" >"$it.actual.2" &&
+
+	git diff "$it^" "$it" -- | sed -e '1,/^@@/d' >"$it.expect.1" &&
+	test_cmp "$it.expect.1" "$it.actual.1" &&
+
+	git diff "$it^2" "$it" -- | sed -e '1,/^@@/d' >"$it.expect.2" &&
+	test_cmp "$it.expect.2" "$it.actual.2"
+}
+
+test_expect_success setup '
+	>file &&
+	git add file &&
+	test_tick &&
+	git commit -m initial &&
+
+	git branch withone &&
+	git branch sansone &&
+
+	git checkout withone &&
+	setup_helper one withone sidewithone &&
+
+	git checkout sansone &&
+	setup_helper "" sansone sidesansone
+'
+
+test_expect_success 'check combined output (1)' '
+	git show sidewithone -- >sidewithone &&
+	verify_helper sidewithone
+'
+
+test_expect_success 'check combined output (2)' '
+	git show sidesansone -- >sidesansone &&
+	verify_helper sidesansone
+'
+
+test_expect_success 'diagnose truncated file' '
+	>file &&
+	git add file &&
+	git commit --amend -C HEAD &&
+	git show >out &&
+	grep "diff --cc file" out
+'
+
+test_done