public void OnUploadResumed()
        {
            // arrange
            var vm = new FieldFileViewModel();

            short count = 0;
            Mock.NonPublic.Arrange(vm, "RaisePropertyChanged", "IsFocused").DoInstead(() => { count++; });

            // act
            vm.OnUploadResumed(null, new RoutedEventArgs());

            // assert
            Assert.AreEqual(2, count);
        }