diff --git a/core/sequences/sequences-tests.factor b/core/sequences/sequences-tests.factor
index 37e03ff9d2..c578e1ce49 100644
--- a/core/sequences/sequences-tests.factor
+++ b/core/sequences/sequences-tests.factor
@@ -330,3 +330,5 @@ USE: make
 
 [ { { { 1 "a" } { 1 "b" } } { { 2 "a" } { 2 "b" } } } ]
 [ { 1 2 } { "a" "b" } cartesian-product ] unit-test
+
+[ 4 ] [ { 1 1 } [ 1 + ] [ + ] map-reduce ] unit-test