1 files changed, 67 insertions, 0 deletions
diff --git a/t/t4031-diff-rewrite-binary.sh b/t/t4031-diff-rewrite-binary.sh
new file mode 100755
index 0000000000..a894c60622
--- /dev/null
+++ b/t/t4031-diff-rewrite-binary.sh
@@ -0,0 +1,67 @@
+#!/bin/sh
+
+test_description='rewrite diff on binary file'
+
+. ./test-lib.sh
+
+# We must be large enough to meet the MINIMUM_BREAK_SIZE
+# requirement.
+make_file() {
+	# common first line to help identify rewrite versus regular diff
+	printf "=\n" >file
+	for i in 1 2 3 4 5 6 7 8 9 10
+	do
+		for j in 1 2 3 4 5 6 7 8 9
+		do
+			for k in 1 2 3 4 5
+			do
+				printf "$1\n"
+			done
+		done
+	done >>file
+}
+
+test_expect_success 'create binary file with changes' '
+	make_file "\\0" &&
+	git add file &&
+	make_file "\\01"
+'
+
+test_expect_success 'vanilla diff is binary' '
+	git diff >diff &&
+	grep "Binary files a/file and b/file differ" diff
+'
+
+test_expect_success 'rewrite diff is binary' '
+	git diff -B >diff &&
+	grep "dissimilarity index" diff &&
+	grep "Binary files a/file and b/file differ" diff
+'
+
+test_expect_success 'rewrite diff can show binary patch' '
+	git diff -B --binary >diff &&
+	grep "dissimilarity index" diff &&
+	grep "GIT binary patch" diff
+'
+
+{
+	echo "#!$SHELL_PATH"
+	cat <<'EOF'
+perl -e '$/ = undef; $_ = <>; s/./ord($&)/ge; print $_' < "$1"
+EOF
+} >dump
+chmod +x dump
+
+test_expect_success 'setup textconv' '
+	echo file diff=foo >.gitattributes &&
+	git config diff.foo.textconv "$PWD"/dump
+'
+
+test_expect_success 'rewrite diff respects textconv' '
+	git diff -B >diff &&
+	grep "dissimilarity index" diff &&
+	grep "^-61" diff &&
+	grep "^-0" diff
+'
+
+test_done