_02_04_ make tests more general

src/test/java/linkedlist/_02_04_PartitionTest.java

@@ -2,6 +2,11 @@
 
 import org.junit.Test;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import static junit.framework.TestCase.fail;
 import static org.junit.Assert.assertEquals;
 
 public class _02_04_PartitionTest {
@@ -15,27 +20,59 @@ public void withEmptyList() {
 
     @Test
     public void withSortedList() {
-        assertEquals(LinkedListNode.of(1, 2, 3), s.partition(LinkedListNode.of(1, 2, 3), 2));
+        assertPartition(LinkedListNode.of(1, 2, 3), s.partition(LinkedListNode.of(1, 2, 3), 2), 2);
     }
 
     @Test
     public void withSortedList_AndOutOfListX() {
-        assertEquals(LinkedListNode.of(3, 2, 1), s.partition(LinkedListNode.of(1, 2, 3), 4));
+        assertPartition(LinkedListNode.of(3, 2, 1), s.partition(LinkedListNode.of(1, 2, 3), 4), 4);
     }
 
     @Test
     public void withSortedList_AndOutOfListX_Smaller() {
-        assertEquals(LinkedListNode.of(1, 2, 3), s.partition(LinkedListNode.of(1, 2, 3), 0));
+        assertPartition(LinkedListNode.of(1, 2, 3), s.partition(LinkedListNode.of(1, 2, 3), 0), 0);
     }
 
     @Test
     public void withUnSortedList() {
-        assertEquals(LinkedListNode.of(1, 2, 4, 3, 5), s.partition(LinkedListNode.of(4, 3, 2, 5, 1), 3));
+        assertPartition(LinkedListNode.of(1, 2, 4, 3, 5), s.partition(LinkedListNode.of(4, 3, 2, 5, 1), 3), 3);
     }
 
     @Test
     public void withUnSortedList_AndOutOfScopeX() {
-        assertEquals(LinkedListNode.of(1, 2, 4, 3, 6), s.partition(LinkedListNode.of(3, 4, 2, 6, 1), 5));
+        assertPartition(LinkedListNode.of(1, 2, 4, 3, 6), s.partition(LinkedListNode.of(3, 4, 2, 6, 1), 5), 5);
+    }
+
+    private void assertPartition(LinkedListNode input, LinkedListNode actual, int x) {
+        List<Integer> original = toList(input);
+        List<Integer> result = toList(actual);
+
+        // Check that elements are the same (ignoring order)
+        List<Integer> originalSorted = new ArrayList<>(original);
+        List<Integer> resultSorted = new ArrayList<>(result);
+        Collections.sort(originalSorted);
+        Collections.sort(resultSorted);
+        assertEquals("Partitioned list must contain the same elements", originalSorted, resultSorted);
+
+        // Check partition order
+        boolean seenRightPartition = false;
+        for (int value : result) {
+            if (value < x) {
+                if (seenRightPartition) {
+                    fail("Elements less than x appeared after elements greater than or equal to x");
+                }
+            } else {
+                seenRightPartition = true;
+            }
+        }
     }
 
-}
+    private List<Integer> toList(LinkedListNode node) {
+        List<Integer> list = new ArrayList<>();
+        while (node != null) {
+            list.add(node.val);
+            node = node.next;
+        }
+        return list;
+    }
+}