BAEL-382 Add extension function that works on list

kotlin/src/main/kotlin/com/baeldung/Item.kt

@@ -1,4 +1,4 @@
 package com.baeldung
 
 
-data class Item(val id: String, val name: String)
+data class Item(val id: String, val name: String = "unknown_name")

kotlin/src/main/kotlin/com/baeldung/ListExtension.kt

@@ -0,0 +1,15 @@
+package com.baeldung
+
+import java.util.concurrent.ThreadLocalRandom
+
+
+class ListExtension {
+    fun <T> List<T>.random(): T? {
+        if (this.isEmpty()) return null
+        return get(ThreadLocalRandom.current().nextInt(count()))
+    }
+
+    fun <T> getRandomElementOfList(list: List<T>): T? {
+        return list.random()
+    }
+}

kotlin/src/test/kotlin/com/baeldung/ListExtensionTest.kt

@@ -0,0 +1,18 @@
+package com.baeldung
+
+import org.junit.Test
+import kotlin.test.assertTrue
+
+class ListExtensionTest {
+    @Test
+    fun givenList_whenExecuteExtensionFunctionOnList_shouldReturnRandomElementOfList(){
+        //given
+        val elements = listOf("a", "b", "c")
+
+        //when
+        val result = ListExtension().getRandomElementOfList(elements)
+
+        //then
+        assertTrue(elements.contains(result))
+    }
+}