Add .net9.0 supports

- Enable multiple target frameworks for Test project
- Enable RespectNullable and RequiredConstructor option in Interpreter
  when run on .9.0

Author: voltaney

TouchSenderInterpreter.Test/InterpreterTest.cs

@@ -138,6 +138,39 @@ public void Read_InvalidJson_ReturnsFailureResult(string invalidJson)
             Assert.NotNull(result.ErrorMessage);
         }
 
+        /// <summary>
+        /// Test the Read method with an empty JSON payload.
+        /// 
+        /// for .NET 9.0 or greater, it should return a failure result
+        /// for .NET 8.0 or lower, it should return a success result with null payload
+        /// </summary>
+        [Theory]
+        [InlineData("{}")]
+        [InlineData("{\"Id\":0,\"DeviceInfo\":null,\"SingleTouch\":null}")]
+        public void Read_EmptyJson_ReturnsUnsucceededResult(string invalidJson)
+        {
+            // Log
+            output.WriteLine(invalidJson);
+
+            // Arrange
+            var input = Encoding.UTF8.GetBytes(invalidJson);
+
+            // Act
+            var result = Interpreter.Read(input);
+            output.WriteLine(result.ToString());
+
+            // Assert
+#if NET9_0_OR_GREATER
+            Assert.False(result.IsSuccess);
+            Assert.Null(result.Payload);
+            Assert.NotNull(result.ErrorMessage);
+#else
+            Assert.True(result.IsSuccess);
+            Assert.NotNull(result.Payload);
+            Assert.Null(result.ErrorMessage);
+#endif
+        }
+
         /// <summary>
         /// Test the Equals method with different payloads
         /// </summary>

TouchSenderInterpreter.Test/TouchSenderInterpreter.Test.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
 

TouchSenderInterpreter/Interpreter.cs

@@ -9,7 +9,11 @@ public class Interpreter
 
         private static readonly JsonSerializerOptions _options = new()
         {
-            PropertyNameCaseInsensitive = true
+            PropertyNameCaseInsensitive = true,
+#if NET9_0_OR_GREATER
+            RespectNullableAnnotations = true,
+            RespectRequiredConstructorParameters = true,
+#endif
         };
 
         public static TouchSenderResult Read(byte[] input)

TouchSenderInterpreter/TouchSenderInterpreter.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <Copyright>Copyright (c) Voltaney 2025</Copyright>