Add some simple tests

tests/Jellyfin.Server.Implementations.Tests/HttpServer/ResponseFilterTests.cs

@@ -0,0 +1,16 @@
+using Emby.Server.Implementations.HttpServer;
+using Xunit;
+
+namespace Jellyfin.Server.Implementations.Tests.HttpServer
+{
+    public class HttpServerTests
+    {
+        [Theory]
+        [InlineData("This is a clean string.", "This is a clean string.")]
+        [InlineData("This isn't \n\ra clean string.", "This isn't a clean string.")]
+        public void RemoveControlCharactersTest(string input, string result)
+        {
+            Assert.Equal(result, ResponseFilter.RemoveControlCharacters(input));
+        }
+    }
+}