Split Settings into model, serializer, paths and store

698 lines did all of it at once. The mutable CaptureFromUi callback becomes an
ISettingsCapture the settings view implements.

StarterNG.Tests/SettingsStoreTests.cs

@@ -0,0 +1,131 @@
+using StarterNG.Domain.Settings;
+using StarterNG.Tests.Fakes;
+
+namespace StarterNG.Tests;
+
+public class SettingsStoreTests
+{
+    private const string UserIni = "/home/kolejarz/.config/MaSzyna/eu07.ini";
+
+    private static TestInstallation WithHome(InMemoryFileSystem? files = null)
+    {
+        var installation = new TestInstallation(files);
+        installation.Environment.With("HOME", "/home/kolejarz");
+        return installation;
+    }
+
+    [Fact]
+    public void Settings_are_read_from_the_users_ini()
+    {
+        var installation = WithHome(new InMemoryFileSystem()
+            .WithFile(UserIni, "width 1920\nheight 1080\nfullscreen yes\nlang pl\n"));
+
+        installation.SettingsStore.Load();
+
+        var settings = installation.SettingsStore.Settings;
+        Assert.Equal(1920, settings.Width);
+        Assert.Equal(1080, settings.Height);
+        Assert.True(settings.Fullscreen);
+        Assert.Equal("Polski", settings.Language);
+        Assert.True(settings.LanguageWasSet);
+        Assert.Equal(UserIni, installation.SettingsStore.LoadedFrom);
+    }
+
+    [Fact]
+    public void A_first_run_falls_back_to_the_ini_shipped_with_the_installation()
+    {
+        var installation = WithHome(new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("eu07.ini"), "width 800\n"));
+
+        installation.SettingsStore.Load();
+
+        Assert.Equal(800, installation.SettingsStore.Settings.Width);
+        Assert.Equal(TestInstallation.At("eu07.ini"), installation.SettingsStore.LoadedFrom);
+        // Saving still goes to the user's own file, never back into the installation.
+        Assert.Equal(UserIni, installation.SettingsStore.SavePath);
+    }
+
+    [Fact]
+    public void With_no_ini_at_all_the_defaults_stand()
+    {
+        var installation = WithHome();
+
+        installation.SettingsStore.Load();
+
+        Assert.Equal(1280, installation.SettingsStore.Settings.Width);
+        Assert.False(installation.SettingsStore.Settings.LanguageWasSet);
+    }
+
+    [Fact]
+    public void A_save_round_trips_the_settings()
+    {
+        var installation = WithHome();
+        installation.SettingsStore.Load();
+        installation.SettingsStore.Settings.Width = 2560;
+        installation.SettingsStore.Settings.FieldOfView = 60;
+        installation.SettingsStore.Save();
+
+        var reopened = WithHome(installation.Files);
+        reopened.SettingsStore.Load();
+
+        Assert.Equal(2560, reopened.SettingsStore.Settings.Width);
+        Assert.Equal(60, reopened.SettingsStore.Settings.FieldOfView);
+    }
+
+    [Fact]
+    public void Keys_the_starter_does_not_manage_survive_a_round_trip()
+    {
+        var installation = WithHome(new InMemoryFileSystem()
+            .WithFile(UserIni, "width 1280\nsomethingexotic 42\n"));
+        installation.SettingsStore.Load();
+
+        installation.SettingsStore.Save();
+
+        Assert.Contains("somethingexotic 42", installation.Files.ReadAllText(UserIni));
+    }
+
+    [Fact]
+    public void A_registered_screen_is_asked_for_its_edits_before_a_save()
+    {
+        var installation = WithHome();
+        installation.SettingsStore.Load();
+        installation.SettingsStore.RegisterCapture(new WidthCapture(3840));
+
+        installation.SettingsStore.CaptureAndSave();
+
+        Assert.Equal(3840, installation.SettingsStore.Settings.Width);
+    }
+
+    [Fact]
+    public void An_ini_written_by_someone_else_is_noticed()
+    {
+        var installation = WithHome(new InMemoryFileSystem().WithFile(UserIni, "width 1280\n"));
+        installation.SettingsStore.Load();
+
+        Assert.False(installation.SettingsStore.IsConfigNewerOnDisk());
+
+        installation.Files.LastWriteTimeUtc = installation.Files.LastWriteTimeUtc.AddMinutes(5);
+
+        Assert.True(installation.SettingsStore.IsConfigNewerOnDisk());
+    }
+
+    [Fact]
+    public void On_windows_the_ini_lives_under_appdata()
+    {
+        var installation = new TestInstallation();
+        installation.Environment.AsWindows();
+
+        Assert.Equal(Path.Combine("C:/Users/kolejarz/AppData/Roaming", "MaSzyna", "eu07.ini"),
+                     installation.SettingsPaths.UserConfigPath());
+    }
+
+    /// <summary>Stands in for the settings screen holding an unsaved edit.</summary>
+    private sealed class WidthCapture : StarterNG.Application.ISettingsCapture
+    {
+        private readonly int _width;
+
+        public WidthCapture(int width) => _width = width;
+
+        public void CaptureInto(SimulatorSettings settings) => settings.Width = _width;
+    }
+}