Standard element unassigned or null attributes are now correctly retu…

…rned as null. Improved testability.

HtmlUtilities.Tests/Validated/Standardized/StyleTests.cs

@@ -0,0 +1,13 @@
+using System.Buffers;
+using System.Text;
+
+namespace HtmlUtilities.Validated.Standardized;
+
+public static class StyleTests
+{
+    [Fact]
+    public static void StyleMedia()
+    {
+        Assert.Equal("<style media=test></style>", new Style { Media = "test" }.ToString());
+    }
+}

HtmlUtilities/Validated/StandardElement.cs

@@ -1,4 +1,6 @@
-using System.Runtime.CompilerServices;
+using System.Buffers;
+using System.Runtime.CompilerServices;
+using System.Text;
 
 namespace HtmlUtilities.Validated;
 
@@ -12,7 +14,7 @@ public abstract class StandardElement
     private readonly Dictionary<string, ValidatedAttributeValue> attributes = [];
 
     private protected ValidatedAttributeValue? GetAttribute([CallerMemberName] string name = null!)
-        => attributes.TryGetValue(name, out var value) ? value : null;
+        => attributes.TryGetValue(name, out var value) ? value : (ValidatedAttributeValue?)null;
 
     private protected void SetAttribute(ValidatedAttributeValue? value, [CallerMemberName] string name = null!)
     {
@@ -58,4 +60,15 @@ private protected void Write(AttributeWriter writer)
         writer.Write(" id"u8, Id);
         writer.Write(" title"u8, Title);
     }
+
+    /// <inheritdoc/>
+    public override string ToString()
+    {
+        var buffer = new ArrayBufferWriter<byte>();
+        var writer = new HtmlWriter(buffer);
+
+        Write(writer);
+
+        return Encoding.UTF8.GetString(buffer.WrittenSpan);
+    }
 }