diff --git a/core-kotlin-2/src/test/kotlin/com/baeldung/lists/ListsTest.kt b/core-kotlin-2/src/test/kotlin/com/baeldung/lists/ListsUnitTest.kt
similarity index 68%
rename from core-kotlin-2/src/test/kotlin/com/baeldung/lists/ListsTest.kt
rename to core-kotlin-2/src/test/kotlin/com/baeldung/lists/ListsUnitTest.kt
index 8515a6f078..1e7136d08b 100644
--- a/core-kotlin-2/src/test/kotlin/com/baeldung/lists/ListsTest.kt
+++ b/core-kotlin-2/src/test/kotlin/com/baeldung/lists/ListsUnitTest.kt
@@ -1,10 +1,10 @@
-package com.baeldung.lambda
+package com.baeldung.lists
 
 import org.junit.jupiter.api.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
 
-class ListsTest {
+class ListsUnitTest {
 
     var batmans: List<String> = listOf("Christian Bale", "Michael Keaton", "Ben Affleck", "George Clooney")
 
@@ -22,4 +22,11 @@ class ListsTest {
         assertTrue(theCoolestBatmans.contains("Christian Bale") && theCoolestBatmans.contains("Michael Keaton"))
     }
 
+    @Test
+    fun whenFilterNotWithPredicate_thenMatchingItemsAreReturned() {
+        //Returns a list containing only elements not matching the given predicate.
+        val theMehBatmans = batmans.filterNot { actor -> actor.contains("a") }
+        assertTrue(!theMehBatmans.contains("Christian Bale") && !theMehBatmans.contains("Michael Keaton"))
+    }
+
 }
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