cursor-lang/CursorLang.Tests/Services/MainWindowPresenterTests.cs

using System.Windows;
using CursorLang.Services;
using CursorLang.Tests.Infrastructure;

namespace CursorLang.Tests.Services;

/// <summary>
/// The fate of the settings window: it comes and goes, and the application
/// outlives it either way.
/// </summary>
/// <remarks>
/// The window has to be alive for real — showing and hiding are the point here —
/// so it is kept fully transparent and off the taskbar.
/// </remarks>
public sealed class MainWindowPresenterTests
{
    [Fact]
    public void The_close_button_hides_the_window_instead_of_closing_it()
    {
        Sta.Run(() =>
        {
            var presenter = new MainWindowPresenter(new MainWindowPlacement());

            Open(presenter, window =>
            {
                window.Close();

                Assert.False(window.IsVisible);
                Assert.False(presenter.IsShown);

                // The window is hidden rather than closed: a closed one would
                // refuse to be shown again
                presenter.Show();
                Assert.True(window.IsVisible);
            });
        });
    }

    [Fact]
    public void The_minimise_button_hides_the_window_as_well()
    {
        Sta.Run(() =>
        {
            var presenter = new MainWindowPresenter(new MainWindowPlacement());

            Open(presenter, window =>
            {
                window.WindowState = WindowState.Minimized;

                Assert.False(window.IsVisible);

                // And the window is left in the state the next show needs:
                // a minimised one would come back as an icon on the taskbar
                Assert.Equal(WindowState.Normal, window.WindowState);
            });
        });
    }

    [Fact]
    public void A_hidden_window_comes_back_on_request()
    {
        Sta.Run(() =>
        {
            var presenter = new MainWindowPresenter(new MainWindowPlacement());

            Open(presenter, window =>
            {
                presenter.Hide();
                Assert.False(presenter.IsShown);

                presenter.Show();

                Assert.True(window.IsVisible);
                Assert.True(presenter.IsShown);
                Assert.Equal(WindowState.Normal, window.WindowState);
            });
        });
    }

    // On the way out of the application the window closes for real: otherwise
    // the exit from the tray menu would run into the very same refusal
    [Fact]
    public void The_window_closes_once_the_application_is_quitting()
    {
        Sta.Run(() =>
        {
            var presenter = new MainWindowPresenter(new MainWindowPlacement());

            Open(presenter, window =>
            {
                presenter.AllowClose();
                window.Close();

                Assert.Throws<InvalidOperationException>(window.Show);
            });
        });
    }

    // Without a notification area there is no way back to a hidden window,
    // so the window goes back to closing when told to close
    [Fact]
    public void A_window_let_go_of_behaves_the_usual_way()
    {
        Sta.Run(() =>
        {
            var presenter = new MainWindowPresenter(new MainWindowPlacement());

            Open(presenter, window =>
            {
                presenter.Detach();
                window.Close();

                Assert.Throws<InvalidOperationException>(window.Show);
            });

            // Letting go twice is what happens when the application quits
            // right after: it is no reason to fail
            presenter.Detach();
        });
    }

    [Fact]
    public void With_no_window_attached_nothing_happens()
    {
        var presenter = new MainWindowPresenter(new MainWindowPlacement());

        presenter.Show();
        presenter.Hide();

        Assert.False(presenter.IsShown);
    }

    private static void Open(MainWindowPresenter presenter, Action<Window> check)
    {
        var window = new Window
        {
            // The window is needed alive, but not in sight
            Opacity = 0,
            ShowInTaskbar = false,
            ShowActivated = false,
            Width = 100,
            Height = 100,
        };

        presenter.Attach(window);

        try
        {
            window.Show();
            check(window);
        }
        finally
        {
            presenter.AllowClose();
            window.Close();
        }
    }
}