1 files changed, 99 insertions, 0 deletions
diff --git a/third_party/git/t/t4022-diff-rewrite.sh b/third_party/git/t/t4022-diff-rewrite.sh
new file mode 100755
index 000000000000..6d1c3d949c78
--- /dev/null
+++ b/third_party/git/t/t4022-diff-rewrite.sh
@@ -0,0 +1,99 @@
+#!/bin/sh
+
+test_description='rewrite diff'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+
+	cat "$TEST_DIRECTORY"/../COPYING >test &&
+	git add test &&
+	tr \
+	  "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+	  "nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM" \
+	  <"$TEST_DIRECTORY"/../COPYING >test &&
+	echo "to be deleted" >test2 &&
+	blob=$(git hash-object test2) &&
+	blob=$(git rev-parse --short $blob) &&
+	git add test2
+
+'
+
+test_expect_success 'detect rewrite' '
+
+	actual=$(git diff-files -B --summary test) &&
+	verbose expr "$actual" : " rewrite test ([0-9]*%)$"
+
+'
+
+cat >expect <<EOF
+diff --git a/test2 b/test2
+deleted file mode 100644
+index $blob..0000000
+--- a/test2
++++ /dev/null
+@@ -1 +0,0 @@
+-to be deleted
+EOF
+test_expect_success 'show deletion diff without -D' '
+
+	rm test2 &&
+	git diff -- test2 >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<EOF
+diff --git a/test2 b/test2
+deleted file mode 100644
+index $blob..0000000
+EOF
+test_expect_success 'suppress deletion diff with -D' '
+
+	git diff -D -- test2 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'show deletion diff with -B' '
+
+	git diff -B -- test >actual &&
+	grep "Linus Torvalds" actual
+'
+
+test_expect_success 'suppress deletion diff with -B -D' '
+
+	git diff -B -D -- test >actual &&
+	grep -v "Linus Torvalds" actual
+'
+
+test_expect_success 'prepare a file that ends with an incomplete line' '
+	test_seq 1 99 >seq &&
+	printf 100 >>seq &&
+	git add seq &&
+	git commit seq -m seq
+'
+
+test_expect_success 'rewrite the middle 90% of sequence file and terminate with newline' '
+	test_seq 1 5 >seq &&
+	test_seq 9331 9420 >>seq &&
+	test_seq 96 100 >>seq
+'
+
+test_expect_success 'confirm that sequence file is considered a rewrite' '
+	git diff -B seq >res &&
+	grep "dissimilarity index" res
+'
+
+test_expect_success 'no newline at eof is on its own line without -B' '
+	git diff seq >res &&
+	grep "^\\\\ " res &&
+	! grep "^..*\\\\ " res
+'
+
+test_expect_success 'no newline at eof is on its own line with -B' '
+	git diff -B seq >res &&
+	grep "^\\\\ " res &&
+	! grep "^..*\\\\ " res
+'
+
+test_done
+