TheAlgorithms
diff --git a/‎src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
Lines changed: 3 additions & 0 deletions b/‎src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
Lines changed: 3 additions & 0 deletions
diff --git a/‎src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
Lines changed: 0 additions & 44 deletions b/‎src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
Lines changed: 0 additions & 44 deletions
diff --git a/‎src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java
Lines changed: 6 additions & 0 deletions b/‎src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java
Lines changed: 6 additions & 0 deletions
diff --git a/‎src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java
Lines changed: 0 additions & 58 deletions b/‎src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java
Lines changed: 0 additions & 58 deletions
@@ -38,6 +38,9 @@ private ReverseStack() {
      * @param stack the stack to reverse; should not be null
      */
     public static void reverseStack(Stack<Integer> stack) {
+        if (stack == null) {
+            throw new IllegalArgumentException("Stack cannot be null");
+        }
         if (stack.isEmpty()) {
             return;
         }
 
@@ -1,13 +1,19 @@
 package com.thealgorithms.datastructures.stacks;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.Stack;
 import org.junit.jupiter.api.Test;
 
 class ReverseStackTest {
 
+    @Test
+    void testReverseNullStack() {
+        assertThrows(IllegalArgumentException.class, () -> ReverseStack.reverseStack(null), "Reversing a null stack should throw an IllegalArgumentException.");
+    }
+
     @Test
     void testReverseEmptyStack() {
         Stack<Integer> stack = new Stack<>();