Enhance docs, add more tests in EndianConverter (TheAlgorithms#5921)

Hardvan · web-flow · commit b5a097c56a92 · 2024-10-26T21:35:36.000+03:00
diff --git a/src/main/java/com/thealgorithms/conversions/EndianConverter.java b/src/main/java/com/thealgorithms/conversions/EndianConverter.java
@@ -1,22 +1,46 @@
 package com.thealgorithms.conversions;
 
 /**
- * Converts between big-endian and little-endian formats.
- * Big-endian is the most significant byte first, while little-endian is the least significant byte first.
- * Big-endian to little-endian: 0x12345678 -> 0x78563412
+ * Utility class for converting integers between big-endian and little-endian formats.
+ * <p>
+ * Endianness defines how byte sequences represent multi-byte data types:
+ * <ul>
+ *   <li><b>Big-endian</b>: The most significant byte (MSB) comes first.</li>
+ *   <li><b>Little-endian</b>: The least significant byte (LSB) comes first.</li>
+ * </ul>
+ * <p>
+ * Example conversion:
+ * <ul>
+ *   <li>Big-endian to little-endian: {@code 0x12345678} → {@code 0x78563412}</li>
+ *   <li>Little-endian to big-endian: {@code 0x78563412} → {@code 0x12345678}</li>
+ * </ul>
  *
- * Little-endian to big-endian: 0x12345678 -> 0x78563412
+ * <p>Note: Both conversions in this utility are equivalent since reversing the bytes is symmetric.</p>
+ *
+ * <p>This class only supports 32-bit integers.</p>
  *
  * @author Hardvan
  */
 public final class EndianConverter {
     private EndianConverter() {
     }
 
+    /**
+     * Converts a 32-bit integer from big-endian to little-endian.
+     *
+     * @param value the integer in big-endian format
+     * @return the integer in little-endian format
+     */
     public static int bigToLittleEndian(int value) {
         return Integer.reverseBytes(value);
     }
 
+    /**
+     * Converts a 32-bit integer from little-endian to big-endian.
+     *
+     * @param value the integer in little-endian format
+     * @return the integer in big-endian format
+     */
     public static int littleToBigEndian(int value) {
         return Integer.reverseBytes(value);
     }
diff --git a/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java b/src/test/java/com/thealgorithms/conversions/EndianConverterTest.java
@@ -2,21 +2,34 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class EndianConverterTest {
 
-    @Test
-    public void testBigToLittleEndian() {
-        assertEquals(0x78563412, EndianConverter.bigToLittleEndian(0x12345678));
-        assertEquals(0x00000000, EndianConverter.bigToLittleEndian(0x00000000));
-        assertEquals(0x00000001, EndianConverter.bigToLittleEndian(0x01000000));
+    @ParameterizedTest
+    @CsvSource({
+        "0x78563412, 0x12345678", "0x00000000, 0x00000000", "0x00000001, 0x01000000",
+        "0xFFFFFFFF, 0xFFFFFFFF", // -1 in two's complement
+        "0x0000007F, 0x7F000000" // Positive boundary case
+    })
+    public void
+    testLittleToBigEndian(String inputHex, String expectedHex) {
+        int input = (int) Long.parseLong(inputHex.substring(2), 16); // Convert hex string to int
+        int expected = (int) Long.parseLong(expectedHex.substring(2), 16); // Convert hex string to int
+        assertEquals(expected, EndianConverter.littleToBigEndian(input));
     }
 
-    @Test
-    public void testLittleToBigEndian() {
-        assertEquals(0x12345678, EndianConverter.littleToBigEndian(0x78563412));
-        assertEquals(0x00000000, EndianConverter.littleToBigEndian(0x00000000));
-        assertEquals(0x01000000, EndianConverter.littleToBigEndian(0x00000001));
+    @ParameterizedTest
+    @CsvSource({
+        "0x12345678, 0x78563412", "0x00000000, 0x00000000", "0x01000000, 0x00000001",
+        "0xFFFFFFFF, 0xFFFFFFFF", // -1 in two's complement
+        "0x7F000000, 0x0000007F" // Positive boundary case
+    })
+    public void
+    testBigToLittleEndian(String inputHex, String expectedHex) {
+        int input = (int) Long.parseLong(inputHex.substring(2), 16); // Convert hex string to int
+        int expected = (int) Long.parseLong(expectedHex.substring(2), 16); // Convert hex string to int
+        assertEquals(expected, EndianConverter.bigToLittleEndian(input));
     }
 }
