Fix bug: interface with get only property generates setter (#40)

* Add failing unit test for interface with get only property.

* Fix bug when interface property has get-only, but still generates setter. By checking if interface had getter or setter before adding it to generated decorator abstract class.

* Add additional property get/set combinations for unit test.

DecoratorGenerator.UnitTests/ILionProperties.cs

@@ -0,0 +1,13 @@
+using DecoratorGenerator;
+
+namespace SampleLibrary;
+
+[Decorate]
+public interface ILionProperties
+{
+    string Name { get; }
+
+    string Color { set; }
+
+    int Age { get; set; }
+}

DecoratorGenerator.UnitTests/LionPropertiesDecorator.generated.cs

@@ -0,0 +1,19 @@
+// <auto-generated/>
+namespace SampleLibrary;
+
+public abstract class LionPropertiesDecorator : ILionProperties
+{
+    private ILionProperties lionProperties;
+
+    protected LionPropertiesDecorator(ILionProperties lionProperties) {
+        this.lionProperties = lionProperties;
+    }
+
+    public virtual string Name { get => lionProperties.Name; }
+
+    public virtual string Color { set => lionProperties.Color = value; }
+
+    public virtual int Age { get => lionProperties.Age; set => lionProperties.Age = value; }
+
+
+}

DecoratorGenerator.UnitTests/Tests.cs

@@ -40,6 +40,28 @@ public async Task OneInterface() {
         }.RunAsync();
     }
 
+    [Test]
+    public async Task OneInterface_Properties() {
+        var source = await ReadCSharpFile<ILionProperties>();
+        var generated = await ReadCSharpFile<LionPropertiesDecorator>();
+
+        await new VerifyCS.Test
+        {
+            TestState = {
+                ReferenceAssemblies = ReferenceAssemblies.Net.Net60,
+                AdditionalReferences =
+                {
+                    implementationAssembly,
+                },
+                Sources = { source },
+                GeneratedSources =
+                {
+                    (typeof(Main), "LionPropertiesDecorator.generated.cs", SourceText.From(generated, Encoding.UTF8, SourceHashAlgorithm.Sha256)),
+                },
+            },
+        }.RunAsync();
+    }
+
     [Test]
     public async Task OneInterface_NestedNamespace() {
         var source = await ReadCSharpFile<INested>();

DecoratorGenerator/OutputGenerator.cs

@@ -65,17 +65,30 @@ public abstract class {className} : {@interface.Name}
             var displayProperties = properties.Select(property => {
                 var formattedAccessibility = property.DeclaredAccessibility.ToString().ToLower();
                 var signature = $@"{formattedAccessibility} virtual {property.Type} {property.Name}";
-                var call = $@"get => {targetFieldName}.{property.Name}; set => {targetFieldName}.{property.Name} = value;";
+
+
+                var propertyMethods = new List<string>();
+
+                if (property.GetMethod != null) {
+                    propertyMethods.Add($@"get => {targetFieldName}.{property.Name};");
+                }
+
+                if (property.SetMethod != null) {
+                    propertyMethods.Add($@"set => {targetFieldName}.{property.Name} = value;");
+                }
+
+                var call = string.Join(" ", propertyMethods);
 
                 return (signature, call, string.Empty);
             });
+
             return displayProperties;
         }
 
         private static IEnumerable<string> FormatDisplayMethods(IEnumerable<(string signature, string call, ITypeSymbol returnType)> displayMethods) {
             return displayMethods.Select(method => {
                 return
-$@"    {method.signature} {{
+    $@"    {method.signature} {{
         {(method.returnType.Name == "Void" ? string.Empty : "return ")}{method.call};
     }}";
             });