Test 'checkout -m -- path'

Signed-off-by: Pete Harlan <pgit@pcharlan.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t2023-checkout-m.sh

@@ -0,0 +1,47 @@
+#!/bin/sh
+
+test_description='checkout -m -- <conflicted path>
+
+Ensures that checkout -m on a resolved file restores the conflicted file'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	test_tick &&
+	test_commit both.txt both.txt initial &&
+	git branch topic &&
+	test_commit modified_in_master both.txt in_master &&
+	test_commit added_in_master each.txt in_master &&
+	git checkout topic &&
+	test_commit modified_in_topic both.txt in_topic &&
+	test_commit added_in_topic each.txt in_topic
+'
+
+test_must_fail git merge master
+
+clean_branchnames () {
+	# Remove branch names after conflict lines
+	sed 's/^\([<>]\{5,\}\) .*$/\1/'
+}
+
+test_expect_success '-m restores 2-way conflicted+resolved file' '
+	cp each.txt each.txt.conflicted &&
+	echo resolved >each.txt &&
+	git add each.txt &&
+	git checkout -m -- each.txt &&
+	clean_branchnames <each.txt >each.txt.cleaned &&
+	clean_branchnames <each.txt.conflicted >each.txt.conflicted.cleaned &&
+	test_cmp each.txt.conflicted.cleaned each.txt.cleaned
+'
+
+test_expect_success '-m restores 3-way conflicted+resolved file' '
+	cp both.txt both.txt.conflicted &&
+	echo resolved >both.txt &&
+	git add both.txt &&
+	git checkout -m -- both.txt &&
+	clean_branchnames <both.txt >both.txt.cleaned &&
+	clean_branchnames <both.txt.conflicted >both.txt.conflicted.cleaned &&
+	test_cmp both.txt.conflicted.cleaned both.txt.cleaned
+'
+
+test_done