WpfViewModelFirst/WpfViewModelFirst.Tests/MainWindowViewModelTests.cs

using Moq;
using WpfViewModelFirst.Part1;
using WpfViewModelFirst.Part2;

namespace WpfViewModelFirst.Tests
{
    public class MainWindowViewModelTests
    {
        [Fact]
        public void Part1WillSetPart1ViewModelToCurrentViewModel()
        {
            Part1ViewModel part1ViewModel = new(() => _ = true);
            Mock<IViewModelFactory> mockViewModelFactory = new Mock<IViewModelFactory>();
            mockViewModelFactory.Setup(vmf => vmf.GetPart1ViewModel(It.IsAny<Action>()))
                .Returns(part1ViewModel);
            MainWindowViewModel main = new(mockViewModelFactory.Object);
            main.Part1(null);
            Assert.Equal(part1ViewModel, main.CurrentViewModel);
        }
        [Fact]
        public void Part1CallbackIsSuccessfull()
        {
            Mock<IViewModelFactory> mockViewModelFactory = new Mock<IViewModelFactory>();
            mockViewModelFactory.Setup(vmf => vmf.GetPart1ViewModel(It.IsAny<Action>()))
                .Returns(() => new Part1ViewModel(() => Task.Delay(0)))
                .Callback<Action>(c => c.Invoke());
            mockViewModelFactory.Setup(vmf => vmf.GetPart2ViewModel())
                .Returns(() => new Part2ViewModel());
            MainWindowViewModel main = new(mockViewModelFactory.Object);
            main.Part1(null);
            Assert.IsType<Part2ViewModel>(main.CurrentViewModel);
        }
    }
}