diff --git a/usr.bin/lockf/tests/lockf_test.sh b/usr.bin/lockf/tests/lockf_test.sh
--- a/usr.bin/lockf/tests/lockf_test.sh
+++ b/usr.bin/lockf/tests/lockf_test.sh
@@ -328,6 +328,23 @@
 	    lockf -wt 0 "testlock" sleep 0
 }
 
+atf_test_case fdlockspin
+fdlockspin_head()
+{
+	atf_set "descr" "Don't spin when locking a file descriptor"
+}
+fdlockspin_body()
+{
+	# Start background locker and give it time to get settled
+	lockf foo sleep 2 & sleep 1
+	# Start foreground locker in fdlock mode
+	atf_check ktrace -tc lockf -t 3 0 <foo
+	# Background locker quit and foreground locker succeeded
+	atf_check -o save:trace kdump -tc
+	# Check how many times foreground locker called flock()
+	atf_check -o inline:"2\n" egrep -c 'CALL +flock' trace
+}
+
 atf_init_test_cases()
 {
 	atf_add_test_case badargs
@@ -341,4 +358,5 @@
 	atf_add_test_case writepid
 	atf_add_test_case writepid_keep
 	atf_add_test_case wrlock
+	atf_add_test_case fdlockspin
 }