1 files changed, 19 insertions, 0 deletions

diff --git a/usr.bin/diff/tests/diff_test.sh b/usr.bin/diff/tests/diff_test.sh
index b499bb709cdd..d28eeba9604d 100755
--- a/usr.bin/diff/tests/diff_test.sh
+++ b/usr.bin/diff/tests/diff_test.sh
@@ -423,6 +423,24 @@ prleak_body()
 	atf_check diff -rul a b
 }
 
+same_head()
+{
+	atf_set "descr" "Don't diff a file or directory with itself"
+}
+same_body()
+{
+	local n=256
+	mkdir a
+	for hi in $(jot -w%02x $n 0) ; do
+		mkdir a/$hi
+		for lo in $(jot -w%02x $n 0) ; do
+			echo "$hi$lo" >a/$hi/$lo
+		done
+	done
+	ln -s a b
+	atf_check timeout 1s diff -rqs a b
+}
+
 atf_init_test_cases()
 {
 	atf_add_test_case simple
@@ -453,4 +471,5 @@ atf_init_test_cases()
 	atf_add_test_case bigc
 	atf_add_test_case bigu
 	atf_add_test_case prleak
+	atf_add_test_case same
 }