added test cases

Author: ishanki19-pixel

src/test/java/com/thealgorithms/bitmanipulation/LowestSetBitTest.java

@@ -1,35 +1,43 @@
 package com.thealgorithms.bitmanipulation;
-import static org.junit.jupiter.api.Assertions.*;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import org.junit.jupiter.api.Test;
-import com.thealgorithms.bitmanipulation.LowestSetBit;
 
 public class LowestSetBitTest {
 
     LowestSetBit lowestSetBit = new LowestSetBit();
 
     @Test
     public void testIsolateLowestSetBit() {
-        // Test with positive number
+        // Test with regular positive numbers
         assertEquals(1, lowestSetBit.isolateLowestSetBit(5));  // 5 in binary is 101, the lowest set bit is 1
         assertEquals(2, lowestSetBit.isolateLowestSetBit(6));  // 6 in binary is 110, the lowest set bit is 2
         assertEquals(4, lowestSetBit.isolateLowestSetBit(12)); // 12 in binary is 1100, the lowest set bit is 4
 
-        // Test with negative number
+        // Test with powers of two
+        assertEquals(1, lowestSetBit.isolateLowestSetBit(1));  // 1 in binary is 1, the lowest set bit is 1
+        assertEquals(2, lowestSetBit.isolateLowestSetBit(2));  // 2 in binary is 10, the lowest set bit is 2
+        assertEquals(4, lowestSetBit.isolateLowestSetBit(4));  // 4 in binary is 100, the lowest set bit is 4
+
+        // Test with negative numbers
         assertEquals(1, lowestSetBit.isolateLowestSetBit(-5)); // -5 in binary (two's complement) still has 1 as the lowest set bit
         assertEquals(2, lowestSetBit.isolateLowestSetBit(-6)); // -6 in binary has 2 as the lowest set bit
 
         // Test with zero
         assertEquals(0, lowestSetBit.isolateLowestSetBit(0));  // Edge case: 0 should return 0
+
+        // Test with number having all bits set
+        assertEquals(1, lowestSetBit.isolateLowestSetBit(-1)); // -1 in two's complement has all bits set, lowest set bit is 1
     }
 
     @Test
     public void testClearLowestSetBit() {
-        // Test with positive number
+        // Test with positive numbers
         assertEquals(4, lowestSetBit.clearLowestSetBit(5));  // 5 in binary is 101, clearing lowest set bit gives 100 (which is 4)
         assertEquals(4, lowestSetBit.clearLowestSetBit(6));  // 6 in binary is 110, clearing lowest set bit gives 100 (which is 4)
         assertEquals(8, lowestSetBit.clearLowestSetBit(12)); // 12 in binary is 1100, clearing lowest set bit gives 1000 (which is 8)
 
-        // Test with negative number
+        // Test with negative numbers
         assertEquals(-6, lowestSetBit.clearLowestSetBit(-5)); // -5 in binary, clearing lowest set bit should give -6
         assertEquals(-8, lowestSetBit.clearLowestSetBit(-6)); // -6 in binary, clearing lowest set bit should give -8