public void ShouldSetRegionContextOnContextChange()
        {
            var behavior = new BindRegionContextToDependencyObjectBehavior();
            var region   = new MockPresentationRegion();
            var view     = new MockDependencyObject();

            region.Add(view);
            behavior.Region = region;
            region.Context  = "MyContext";
            behavior.Attach();
            Assert.AreEqual("MyContext", RegionContext.GetObservableContext(view).Value);

            region.Context = "MyNewContext";
            region.OnPropertyChange("Context");

            Assert.AreEqual("MyNewContext", RegionContext.GetObservableContext(view).Value);
        }