Add parameterized tests for BitSwap (#6347)

src/main/java/com/thealgorithms/bitmanipulation/BitSwap.java

@@ -1,12 +1,27 @@
 package com.thealgorithms.bitmanipulation;
 
+/**
+ * Utility class for performing bit-swapping operations on integers.
+ * This class cannot be instantiated.
+ */
 public final class BitSwap {
     private BitSwap() {
     }
-    /*
-     * @brief Swaps the bits at the position posA and posB from data
+
+    /**
+     * Swaps two bits at specified positions in an integer.
+     *
+     * @param data The input integer whose bits need to be swapped
+     * @param posA The position of the first bit (0-based, from least significant)
+     * @param posB The position of the second bit (0-based, from least significant)
+     * @return The modified value with swapped bits
+     * @throws IllegalArgumentException if either position is negative or ≥ 32
      */
     public static int bitSwap(int data, final int posA, final int posB) {
+        if (posA < 0 || posA >= Integer.SIZE || posB < 0 || posB >= Integer.SIZE) {
+            throw new IllegalArgumentException("Bit positions must be between 0 and 31");
+        }
+
         if (SingleBitOperations.getBit(data, posA) != SingleBitOperations.getBit(data, posB)) {
             data ^= (1 << posA) ^ (1 << posB);
         }