Fix a unit test on .NET Framework

tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/Test_SourceGeneratorsCodegen.cs

@@ -730,6 +730,7 @@ partial class MyViewModel : ObservableValidator
             }
             """;
 
+#if NET6_0_OR_GREATER
         string result = """
             // <auto-generated/>
             #pragma warning disable
@@ -787,6 +788,64 @@ public partial string Name
                 }
             }
             """;
+#else
+        string result = """
+            // <auto-generated/>
+            #pragma warning disable
+            #nullable enable
+            namespace MyApp
+            {
+                /// <inheritdoc/>
+                partial class MyViewModel
+                {
+                    /// <inheritdoc/>
+                    [global::System.CodeDom.Compiler.GeneratedCode("CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator", <ASSEMBLY_VERSION>)]
+                    [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+                    public partial string Name
+                    {
+                        get => field;
+                        set
+                        {
+                            if (!global::System.Collections.Generic.EqualityComparer<string>.Default.Equals(field, value))
+                            {
+                                OnNameChanging(value);
+                                OnNameChanging(default, value);
+                                OnPropertyChanging(global::CommunityToolkit.Mvvm.ComponentModel.__Internals.__KnownINotifyPropertyChangingArgs.Name);
+                                field = value;
+                                ValidateProperty(value, "Name");
+                                OnNameChanged(value);
+                                OnNameChanged(default, value);
+                                OnPropertyChanged(global::CommunityToolkit.Mvvm.ComponentModel.__Internals.__KnownINotifyPropertyChangedArgs.Name);
+                            }
+                        }
+                    }
+
+                    /// <summary>Executes the logic for when <see cref="Name"/> is changing.</summary>
+                    /// <param name="value">The new property value being set.</param>
+                    /// <remarks>This method is invoked right before the value of <see cref="Name"/> is changed.</remarks>
+                    [global::System.CodeDom.Compiler.GeneratedCode("CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator", <ASSEMBLY_VERSION>)]
+                    partial void OnNameChanging(string value);
+                    /// <summary>Executes the logic for when <see cref="Name"/> is changing.</summary>
+                    /// <param name="oldValue">The previous property value that is being replaced.</param>
+                    /// <param name="newValue">The new property value being set.</param>
+                    /// <remarks>This method is invoked right before the value of <see cref="Name"/> is changed.</remarks>
+                    [global::System.CodeDom.Compiler.GeneratedCode("CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator", <ASSEMBLY_VERSION>)]
+                    partial void OnNameChanging(string oldValue, string newValue);
+                    /// <summary>Executes the logic for when <see cref="Name"/> just changed.</summary>
+                    /// <param name="value">The new property value that was set.</param>
+                    /// <remarks>This method is invoked right after the value of <see cref="Name"/> is changed.</remarks>
+                    [global::System.CodeDom.Compiler.GeneratedCode("CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator", <ASSEMBLY_VERSION>)]
+                    partial void OnNameChanged(string value);
+                    /// <summary>Executes the logic for when <see cref="Name"/> just changed.</summary>
+                    /// <param name="oldValue">The previous property value that was replaced.</param>
+                    /// <param name="newValue">The new property value that was set.</param>
+                    /// <remarks>This method is invoked right after the value of <see cref="Name"/> is changed.</remarks>
+                    [global::System.CodeDom.Compiler.GeneratedCode("CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator", <ASSEMBLY_VERSION>)]
+                    partial void OnNameChanged(string oldValue, string newValue);
+                }
+            }
+            """;
+#endif
 
         VerifyGenerateSources(source, new[] { new ObservablePropertyGenerator() }, LanguageVersion.Preview, ("MyApp.MyViewModel.g.cs", result));
     }