tests: make test-apply-criss-cross-rename more robust

I realized that this test does check if git-apply succeeds, but doesn't
tell if it applies patches correctly. So I added test_cmp to check it.

I also added a test which checks swapping three files.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t4130-apply-criss-cross-rename.sh

@@ -15,14 +15,17 @@ create_file() {
 test_expect_success 'setup' '
 	create_file file1 "File1 contents" &&
 	create_file file2 "File2 contents" &&
-	git add file1 file2 &&
+	create_file file3 "File3 contents" &&
+	git add file1 file2 file3 &&
 	git commit -m 1
 '
 
 test_expect_success 'criss-cross rename' '
 	mv file1 tmp &&
 	mv file2 file1 &&
-	mv tmp file2
+	mv tmp file2 &&
+	cp file1 file1-swapped &&
+	cp file2 file2-swapped
 '
 
 test_expect_success 'diff -M -B' '
@@ -32,7 +35,32 @@ test_expect_success 'diff -M -B' '
 '
 
 test_expect_success 'apply' '
-	git apply diff
+	git apply diff &&
+	test_cmp file1 file1-swapped &&
+	test_cmp file2 file2-swapped
+'
+
+test_expect_success 'criss-cross rename' '
+	git reset --hard &&
+	mv file1 tmp &&
+	mv file2 file1 &&
+	mv file3 file2
+	mv tmp file3 &&
+	cp file1 file1-swapped &&
+	cp file2 file2-swapped &&
+	cp file3 file3-swapped
+'
+
+test_expect_success 'diff -M -B' '
+	git diff -M -B > diff &&
+	git reset --hard
+'
+
+test_expect_success 'apply' '
+	git apply diff &&
+	test_cmp file1 file1-swapped &&
+	test_cmp file2 file2-swapped &&
+	test_cmp file3 file3-swapped
 '
 
 test_done