diff --git a/test/unit/spec.js b/test/unit/spec.js
index 7e2115567..48b0fd6ae 100644
--- a/test/unit/spec.js
+++ b/test/unit/spec.js
@@ -19,6 +19,8 @@ test('interface', t => {
     t.type(vm.addCostume, 'function');
     t.type(vm.addBackdrop, 'function');
     t.type(vm.addSound, 'function');
+    t.type(vm.deleteCostume, 'function');
+    t.type(vm.deleteSound, 'function');
     t.type(vm.renameSprite, 'function');
     t.type(vm.deleteSprite, 'function');