added new method to convert byte array to lower case hex-string

added unit test

update ToHex(byte[]) to support mono

added punctuations to unit test summary and parameter description

Replaced with Convert.ToHexString(), public ToHex() + use from Color.ToString()

Adjusted back to a simpler mono compatible version only, with lowered allocation

OpenRA.Test/OpenRA.Game/Sha1Tests.cs

@@ -0,0 +1,35 @@
+using NUnit.Framework;
+using OpenRA.Primitives;
+
+namespace OpenRA.Test
+{
+	[TestFixture]
+	sealed class Sha1Tests
+	{
+		/// <summary>
+		/// https://en.wikipedia.org/wiki/SHA-1#Examples_and_pseudocode.
+		/// </summary>
+		/// <param name="input">The input string.</param>
+		/// <param name="expected">The expected hex string of the SHA1.</param>
+		[TestCase("The quick brown fox jumps over the lazy dog", "2fd4e1c67a2d28fced849ee1bb76e7391b93eb12")]
+		[TestCase("The quick brown fox jumps over the lazy cog", "de9f2c7fd25e1b3afad3e85a0bd17d9b100db4b3")]
+		[TestCase("", "da39a3ee5e6b4b0d3255bfef95601890afd80709")]
+		public void Sha1HexConvert(string input, string expected)
+		{
+			var actual = CryptoUtil.SHA1Hash(input);
+
+			Assert.AreEqual(expected, actual);
+		}
+
+		[TestCase(0xFF0000FF, "0000FF")]
+		[TestCase(0xFF00FFFF, "00FFFF")]
+		[TestCase(0xFFFF00FF, "FF00FF")]
+		[TestCase(0xAAFF00FF, "FF00FFAA")]
+		public void ColorsToHex(uint value, string expected)
+		{
+			var color = Color.FromArgb(value);
+			var actual = color.ToString();
+			Assert.AreEqual(expected, actual);
+		}
+	}
+}