Avalonia/tests/Perspex.Base.UnitTests/PerspexObjectTests_Inheritance.cs

// -----------------------------------------------------------------------
// <copyright file="PerspexObjectTests_Inheritance.cs" company="Steven Kirk">
// Copyright 2015 MIT Licence. See licence.md for more information.
// </copyright>
// -----------------------------------------------------------------------

namespace Perspex.Base.UnitTests
{
    using Xunit;

    public class PerspexObjectTests_Inheritance
    {
        [Fact]
        public void GetValue_Returns_Inherited_Value()
        {
            Class1 parent = new Class1();
            Class2 child = new Class2 { Parent = parent };

            parent.SetValue(Class1.BazProperty, "changed");

            Assert.Equal("changed", child.GetValue(Class1.BazProperty));
        }

        [Fact]
        public void Setting_InheritanceParent_Raises_PropertyChanged_When_Value_Changed_In_Parent()
        {
            bool raised = false;

            Class1 parent = new Class1();
            parent.SetValue(Class1.BazProperty, "changed");

            Class2 child = new Class2();
            child.PropertyChanged += (s, e) =>
                raised = s == child &&
                         e.Property == Class1.BazProperty &&
                         (string)e.OldValue == "bazdefault" &&
                         (string)e.NewValue == "changed";

            child.Parent = parent;

            Assert.True(raised);
        }

        [Fact]
        public void Setting_InheritanceParent_Doesnt_Raise_PropertyChanged_When_Local_Value_Set()
        {
            bool raised = false;

            Class1 parent = new Class1();
            parent.SetValue(Class1.BazProperty, "changed");

            Class2 child = new Class2();
            child.SetValue(Class1.BazProperty, "localvalue");
            child.PropertyChanged += (s, e) => raised = true;

            child.Parent = parent;

            Assert.False(raised);
        }

        [Fact]
        public void Setting_Value_In_InheritanceParent_Raises_PropertyChanged()
        {
            bool raised = false;

            Class1 parent = new Class1();

            Class2 child = new Class2();
            child.PropertyChanged += (s, e) =>
                raised = s == child &&
                         e.Property == Class1.BazProperty &&
                         (string)e.OldValue == "bazdefault" &&
                         (string)e.NewValue == "changed";
            child.Parent = parent;

            parent.SetValue(Class1.BazProperty, "changed");

            Assert.True(raised);
        }

        private class Class1 : PerspexObject
        {
            public static readonly PerspexProperty<string> FooProperty =
                PerspexProperty.Register<Class1, string>("Foo", "foodefault");

            public static readonly PerspexProperty<string> BazProperty =
                PerspexProperty.Register<Class1, string>("Baz", "bazdefault", true);
        }

        private class Class2 : Class1
        {
            static Class2()
            {
                FooProperty.OverrideDefaultValue(typeof(Class2), "foooverride");
            }

            public Class1 Parent
            {
                get { return (Class1)this.InheritanceParent; }
                set { this.InheritanceParent = value; }
            }
        }
    }
}