Add PalindromeSinglyLinkedListTest (#4327)

src/test/java/com/thealgorithms/misc/PalindromeSinglyLinkedListTest.java

@@ -0,0 +1,59 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.thealgorithms.datastructures.lists.SinglyLinkedList;
+import org.junit.jupiter.api.Test;
+
+public class PalindromeSinglyLinkedListTest {
+    @Test
+    public void testWithEmptyList() {
+        assertTrue(PalindromeSinglyLinkedList.isPalindrome(new SinglyLinkedList()));
+    }
+
+    @Test
+    public void testWithSingleElement() {
+        var exampleList = new SinglyLinkedList();
+        exampleList.insert(100);
+        assertTrue(PalindromeSinglyLinkedList.isPalindrome(exampleList));
+    }
+
+    @Test
+    public void testWithListWithOddLengthPositive() {
+        var exampleList = new SinglyLinkedList();
+        exampleList.insert(1);
+        exampleList.insert(2);
+        exampleList.insert(1);
+        assertTrue(PalindromeSinglyLinkedList.isPalindrome(exampleList));
+    }
+
+    @Test
+    public void testWithListWithEvenLengthPositive() {
+        var exampleList = new SinglyLinkedList();
+        exampleList.insert(10);
+        exampleList.insert(20);
+        exampleList.insert(20);
+        exampleList.insert(10);
+        assertTrue(PalindromeSinglyLinkedList.isPalindrome(exampleList));
+    }
+
+    @Test
+    public void testWithListWithOddLengthNegative() {
+        var exampleList = new SinglyLinkedList();
+        exampleList.insert(1);
+        exampleList.insert(2);
+        exampleList.insert(2);
+        assertFalse(PalindromeSinglyLinkedList.isPalindrome(exampleList));
+    }
+
+    @Test
+    public void testWithListWithEvenLengthNegative() {
+        var exampleList = new SinglyLinkedList();
+        exampleList.insert(10);
+        exampleList.insert(20);
+        exampleList.insert(20);
+        exampleList.insert(20);
+        assertFalse(PalindromeSinglyLinkedList.isPalindrome(exampleList));
+    }
+}