Create MiddleOfLinkedListTest.java

Author: AYAZ2006

src/test/java/com/thealgorithms/datastructures/lists/MiddleOfLinkedListTest.java

@@ -0,0 +1,49 @@
+import static org.junit.jupiter.api.Assertions.*;
+import org.junit.jupiter.api.Test;
+
+public class MiddleOfLinkedListTest {
+
+    @Test
+    void testMiddleNodeOddLength() {
+        MiddleOfLinkedList sol = new MiddleOfLinkedList();
+        int[] values = {1, 2, 3, 4, 5}; // Odd-length list
+        ListNode head = MiddleOfLinkedList.createList(values);
+
+        ListNode middle = sol.middleNode(head);
+
+        assertEquals(3, middle.val); // Expect middle to be 3
+    }
+
+    @Test
+    void testMiddleNodeEvenLength() {
+        MiddleOfLinkedList sol = new MiddleOfLinkedList();
+        int[] values = {1, 2, 3, 4, 5, 6}; // Even-length list
+        ListNode head = MiddleOfLinkedList.createList(values);
+
+        ListNode middle = sol.middleNode(head);
+
+        assertEquals(4, middle.val); // Expect middle to be 4 (second middle)
+    }
+
+    @Test
+    void testMiddleNodeSingleElement() {
+        MiddleOfLinkedList sol = new MiddleOfLinkedList();
+        int[] values = {1};
+        ListNode head = MiddleOfLinkedList.createList(values);
+
+        ListNode middle = sol.middleNode(head);
+
+        assertEquals(1, middle.val); // Expect middle to be 1
+    }
+
+    @Test
+    void testMiddleNodeEmptyList() {
+        MiddleOfLinkedList sol = new MiddleOfLinkedList();
+        int[] values = {};
+        ListNode head = MiddleOfLinkedList.createList(values);
+
+        ListNode middle = sol.middleNode(head);
+
+        assertNull(middle); // Expect null for empty list
+    }
+}