[rm-last-element] Remove the Last Element in a List in Kotlin (#657)

Author: sk1418

core-kotlin-modules/core-kotlin-collections-list/src/test/kotlin/com/baeldung/removeTheLastElement/RemoveTheLastElementUnitTest.kt

@@ -0,0 +1,57 @@
+package com.baeldung.removeTheLastElement
+
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class RemoveTheLastElementUnitTest {
+    @Test
+    fun `when calling removeLast() on mutableList then get the expected result`() {
+        val mutableList = mutableListOf("a", "b", "c", "d", "e")
+        mutableList.removeLast()
+        assertEquals(listOf("a", "b", "c", "d"), mutableList)
+
+        assertThrows<NoSuchElementException> {
+            mutableListOf<String>().removeLast()
+        }
+    }
+
+    @Test
+    fun `when calling removeAt() on mutableList then get the expected result`() {
+        val mutableList = mutableListOf("a", "b", "c", "d", "e")
+        mutableList.removeAt(mutableList.lastIndex)
+        assertEquals(listOf("a", "b", "c", "d"), mutableList)
+
+        val emptyMutableList = mutableListOf<String>()
+        assertThrows<IndexOutOfBoundsException> {
+            emptyMutableList.removeAt(emptyMutableList.lastIndex)
+        }.also {
+            assertEquals("Index -1 out of bounds for length 0", it.message)
+        }
+    }
+
+    @Test
+    fun `when calling subList() on read-only list then get the expected result`() {
+        val myList = listOf("a", "b", "c", "d", "e")
+        val result = myList.subList(0, myList.lastIndex)
+        assertEquals(listOf("a", "b", "c", "d"), result)
+
+        val myEmptyList = emptyList<String>()
+        assertThrows<IndexOutOfBoundsException> {
+            myEmptyList.subList(0, myEmptyList.lastIndex)
+        }.also {
+            assertEquals("fromIndex: 0, toIndex: -1", it.message)
+        }
+    }
+
+    @Test
+    fun `when calling droplast() on read-only list then get the expected result`() {
+        val myList = listOf("a", "b", "c", "d", "e")
+        val result = myList.dropLast(1)
+        assertEquals(listOf("a", "b", "c", "d"), result)
+
+        val myEmptyList = emptyList<String>()
+        assertTrue { myEmptyList.dropLast(1).isEmpty() }
+    }
+}