Add tests for ByteArrayExtensions

Source/MoreDotNet.Test/Extensions/Common/ByteArrayExtensions/GetStringTests.cs

@@ -0,0 +1,120 @@
+namespace MoreDotNet.Tests.Extensions.Common.ByteArrayExtensions
+{
+    using System.Linq;
+    using System.Text;
+    using MoreDotNet.Extensions.Common;
+    using Xunit;
+
+    public class GetStringTests
+    {
+        [Fact]
+        public void GetString_NullBuffer_ShouldReturnEmptyString()
+        {
+            byte[] buffer = null;
+            var result = buffer.GetString();
+
+            Assert.Equal(string.Empty, result);
+        }
+
+        [Fact]
+        public void GetString_ZeroLengthBuffer_ShouldReturnEmptyString()
+        {
+            var buffer = new byte[] { };
+            var result = buffer.GetString();
+
+            Assert.Equal(string.Empty, result);
+        }
+
+        [Fact]
+        public void GetString_UTF8_ShouldReturnProperString()
+        {
+            var buffer = GetBytesWithPreamble(Encoding.UTF8, "More Dot Net");
+            var result = buffer.GetString();
+
+            Assert.Equal(result, "More Dot Net");
+        }
+
+        [Fact]
+        public void GetString_Unicode_ShouldReturnProperString()
+        {
+            var buffer = GetBytesWithPreamble(Encoding.Unicode, "More Dot Net");
+            var result = buffer.GetString();
+
+            Assert.Equal(result, "More Dot Net");
+        }
+
+        [Fact]
+        public void GetString_BigEndianUnicode_ShouldReturnProperString()
+        {
+            var buffer = GetBytesWithPreamble(Encoding.BigEndianUnicode, "More Dot Net");
+            var result = buffer.GetString();
+
+            Assert.Equal(result, "More Dot Net");
+        }
+
+        [Fact]
+        public void GetString_UTF32_ShouldReturnProperString()
+        {
+            var buffer = GetBytesWithPreamble(Encoding.UTF32, "More Dot Net");
+            var result = buffer.GetString();
+
+            Assert.Equal(result, "More Dot Net");
+        }
+
+        [Fact]
+        public void GetString_UTF32BigEndian_ShouldReturnProperString()
+        {
+            var buffer = GetBytesWithPreamble(new UTF32Encoding(true, true), "More Dot Net");
+            var result = buffer.GetString();
+
+            Assert.Equal(result, "More Dot Net");
+        }
+
+        [Fact]
+        public void GetString_UTF7_ShouldReturnProperString()
+        {
+            var buffer = GetBytesWithPreamble(Encoding.UTF7, "More Dot Net");
+            var result = buffer.GetString();
+
+            Assert.Equal(result, "More Dot Net");
+        }
+
+        [Fact]
+        public void GetString_ANSI_Specified_ShouldReturnProperString()
+        {
+            var buffer = GetBytesWithPreamble(Encoding.Default, "More Dot Net");
+            var result = buffer.GetString();
+
+            Assert.Equal(result, "More Dot Net");
+        }
+
+        [Fact]
+        public void GetString_NoEncodingSpecified_ShouldReturnProperString()
+        {
+            var buffer = new byte[] { 77, 111, 114, 101, 32, 68, 111, 116, 32, 78, 101, 116 };
+            var result = buffer.GetString();
+
+            Assert.Equal(result, "More Dot Net");
+        }
+
+        [Fact]
+        public void GetString_UTF16WithLeadingZeros_ShouldReturnProperString()
+        {
+            var buffer = new byte[] { 0xff, 0xfe, 0, 0, 77, 0, 111, 0, 97, 0, 114, 0, 101, 0, 32, 0, 68, 0, 111, 0, 116, 0, 32, 0, 78, 0, 101, 0, 116, 0 };
+            var result = buffer.GetString();
+
+            Assert.Equal(result, "\0Moare Dot Net");
+        }
+
+        [Fact]
+        public void GetString_ASCII_ShouldReturnProperString()
+        {
+            var buffer = GetBytesWithPreamble(Encoding.ASCII, "More Dot Net");
+            var result = buffer.GetString();
+
+            Assert.Equal(result, "More Dot Net");
+        }
+
+        private static byte[] GetBytesWithPreamble(Encoding encoding, string data) => encoding.GetPreamble().Concat(encoding.GetBytes(data)).ToArray();
+    }
+}

Source/MoreDotNet.Test/MoreDotNet.Tests.csproj

@@ -117,6 +117,7 @@
     <Compile Include="Extensions\Common\BooleanExtensions\WhenTrueTests.cs" />
     <Compile Include="Extensions\Collections\CollectionExtensions\AddRangeTests.cs" />
     <Compile Include="Extensions\Collections\CollectionExtensions\IsNullOrEmptyTests.cs" />
+    <Compile Include="Extensions\Common\ByteArrayExtensions\GetStringTests.cs" />
     <Compile Include="Extensions\Common\ColorExtensions\ToHexStringTests.cs" />
     <Compile Include="Extensions\Common\ColorExtensions\ToRgbStringTests.cs" />
     <Compile Include="Extensions\Common\ConvertibleExtensions\ToOrDefaultTests.cs" />

Source/MoreDotNet/Extensions/Common/ByteArrayExtensions.cs

@@ -33,18 +33,24 @@ FE FF UTF-16 big endian
             {
                 encoding = Encoding.UTF8;
             }
-            else if (buffer[0] == 0xfe && buffer[1] == 0xff)
+
+            // In addition to preamble check the length to help UTF16 with leading zeros be recognized properly as UTF32 is 4 bytes fixed with and UTF 16 is 2
+            else if (buffer[0] == 0xff && buffer[1] == 0xfe && buffer[2] == 0 && buffer[3] == 0 && buffer.Length % 4 == 0)
+            {
+                encoding = Encoding.UTF32;
+            }
+            else if (buffer[0] == 0 && buffer[1] == 0 && buffer[2] == 0xfe && buffer[3] == 0xff)
+            {
+                encoding = new UTF32Encoding(true, true);
+            }
+            else if (buffer[0] == 0xff && buffer[1] == 0xfe)
             {
                 encoding = Encoding.Unicode;
             }
             else if (buffer[0] == 0xfe && buffer[1] == 0xff)
             {
                 encoding = Encoding.BigEndianUnicode; // utf-16be
             }
-            else if (buffer[0] == 0 && buffer[1] == 0 && buffer[2] == 0xfe && buffer[3] == 0xff)
-            {
-                encoding = Encoding.UTF32;
-            }
             else if (buffer[0] == 0x2b && buffer[1] == 0x2f && buffer[2] == 0x76)
             {
                 encoding = Encoding.UTF7;