test: add unit test for BubbleSort with negative numbers

- Added testBubbleSortNegativeNumbers to verify sorting works correctly with negative values
- Ensures the sort handles negative numbers properly

Author: P-Ved

src/test/java/com/thealgorithms/sorts/BubbleSortTest.java

@@ -160,6 +160,14 @@ public int hashCode() {
         }
     }
 
+    @Test
+    public void bubbleSortNegativeNumbers() {
+        Integer[] inputArray = {5, -1, 7, 0};
+        Integer[] outputArray = bubbleSort.sort(inputArray);
+        Integer[] expectedOutput = {-1, 0, 5, 7};
+        assertArrayEquals(expectedOutput, outputArray);
+    }
+
     @Test
     public void bubbleSortCustomObjects() {
         Person[] inputArray = {