test hex to string implementation and remove unused method

src/UglyToad.PdfPig.Tests/Util/HexTests.cs

@@ -0,0 +1,37 @@
+namespace UglyToad.PdfPig.Tests.Util
+{
+    using System.Collections.Generic;
+    using PdfPig.Util;
+    using Xunit;
+
+    public class HexTests
+    {
+        public static IEnumerable<object[]> TestData => new[]
+        {
+            new object[] {new byte[0], string.Empty},
+            new object[] {new byte[] {37}, "25"},
+            new object[] {new byte[] {0}, "00"},
+            new object[] {new byte[] {255}, "FF"},
+            new object[]
+            {
+                new byte[]
+                {
+                    37, 80, 68,
+                    70, 45, 49,
+                    46, 54, 13,
+                    37
+                },
+                "255044462D312E360D25"
+            }
+        };
+
+        [Theory]
+        [MemberData(nameof(TestData))]
+        public void ConvertsToString(byte[] input, string expected)
+        {
+            var result = Hex.GetString(input);
+
+            Assert.Equal(expected, result);
+        }
+    }
+}

src/UglyToad.PdfPig/Util/Hex.cs

@@ -1,6 +1,6 @@
 namespace UglyToad.PdfPig.Util
 {
-    using System.IO;
+    using System;
     using System.Text;
 
     /**
@@ -8,7 +8,7 @@
      *
      * @author John Hewson
      */
-    internal class Hex
+    internal static class Hex
     {
         /**
          * for hex conversion.
@@ -16,17 +16,18 @@
          * https://stackoverflow.com/questions/2817752/java-code-to-convert-byte-to-hexadecimal
          *
          */
-        private static readonly byte[] HexBytes = { (byte) '0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7',
-            (byte) '8', (byte) '9', (byte) 'A', (byte) 'B', (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F' };
         private static readonly char[] HexChars = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
-
+        
-        private Hex() { }
+        /// <summary>
-
+        /// Returns a hex string for the given byte array.
-        /**
+        /// </summary>
-         * Returns a hex string of the given byte array.
-         */
         public static string GetString(byte[] bytes)
         {
+            if (bytes == null)
+            {
+                throw new ArgumentNullException(nameof(bytes));
+            }
+
             var stringBuilder = new StringBuilder(bytes.Length * 2);
 
             foreach (var b in bytes)
@@ -37,39 +38,14 @@
             return stringBuilder.ToString();
         }
 
-        /**
-         * Writes the given byte as hex value to the given output stream.
-         * @param b the byte to be written
-         * @param output the output stream to be written to
-         * @throws IOException exception if anything went wrong
-         */
-        public static void WriteHexByte(byte b, BinaryWriter output)
-        {
-            output.Write(HexBytes[GetHighNibble(b)]);
-            output.Write(HexBytes[GetLowNibble(b)]);
-        }
-
-        /**
-         * GetLongOrDefault the high nibble of the given byte.
-         * 
-         * @param b the given byte
-         * @return the high nibble
-         */
         private static int GetHighNibble(byte b)
         {
             return (b & 0xF0) >> 4;
         }
 
-        /**
-         * GetLongOrDefault the low nibble of the given byte.
-         * 
-         * @param b the given byte
-         * @return the low nibble
-         */
         private static int GetLowNibble(byte b)
         {
             return b & 0x0F;
         }
     }
-
 }