diff --git a/src/test/java/org/cactoos/scalar/NotTest.java b/src/test/java/org/cactoos/scalar/NotTest.java
index a1bb74a1d..52d5acc71 100644
--- a/src/test/java/org/cactoos/scalar/NotTest.java
+++ b/src/test/java/org/cactoos/scalar/NotTest.java
@@ -50,6 +50,6 @@ void falseToTrue() throws Exception {
             "Must be changed from false to true",
             new Not(new False()).value(),
             new IsEqual<>(new True().value())
-        );
+        ).affirm();
     }
 }