Take the remaining I/O out of the domain and drop AppState.Instance

Scenery translations and load weights get repositories; AppState moves to the
application layer.

StarterNG.Tests/LoadWeightsTests.cs

@@ -0,0 +1,41 @@
+using StarterNG.Classes;
+using StarterNG.Domain.Vehicles;
+using StarterNG.Infrastructure.Vehicles;
+using StarterNG.Tests.Fakes;
+
+namespace StarterNG.Tests;
+
+public class LoadWeightsTests
+{
+    private static LoadWeightsRepository Repository(InMemoryFileSystem files)
+    {
+        var installation = new TestInstallation(files);
+        return new LoadWeightsRepository(files, installation.Paths, installation.Log);
+    }
+
+    [Fact]
+    public void Weights_are_read_from_the_pairs_in_the_file()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("data", "load_weights.txt"),
+                      "{\n  coal : 850 # węgiel\n  sand : 1600\n}");
+
+        var table = Repository(files).Table;
+
+        Assert.Equal(850, table.WeightOf("coal"));
+        Assert.Equal(1600, table.WeightOf("SAND"));
+    }
+
+    [Fact]
+    public void An_unknown_cargo_falls_back_to_the_default_weight()
+    {
+        Assert.Equal(LoadWeightsTable.DefaultWeight,
+                     Repository(new InMemoryFileSystem()).Table.WeightOf("nieznany"));
+    }
+
+    [Fact]
+    public void The_pantograph_pseudo_load_weighs_nothing()
+    {
+        Assert.Equal(0, new LoadWeightsTable().WeightOf(Dynamic.PantState));
+    }
+}

StarterNG.Tests/SceneryTranslationsTests.cs

@@ -0,0 +1,52 @@
+using StarterNG.Infrastructure.Sceneries;
+using StarterNG.Tests.Fakes;
+
+namespace StarterNG.Tests;
+
+public class SceneryTranslationsTests
+{
+    private static string I18n(string file) => Path.Combine(Path.GetFullPath(TestInstallation.At("scenery")),
+                                                            "i18n", file);
+
+    [Fact]
+    public void An_at_reference_is_resolved_against_the_sceneries_own_table()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("scenery", "kato.scn"), "//$d @mission.brief")
+            .WithFile(I18n("kato_en.json"), """{ "mission": { "brief": "Take the stopper to Katowice" } }""");
+        var installation = new TestInstallation(files);
+        var scenery = Assert.Single(installation.Sceneries.LoadAll());
+        var translations = new SceneryTranslations(files, installation.Log);
+
+        translations.LoadFor(scenery, "en");
+
+        Assert.Equal("Take the stopper to Katowice", scenery.LocalizedDescription(translations));
+    }
+
+    [Fact]
+    public void The_users_language_is_layered_over_english()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("scenery", "kato.scn"), "//$d @brief")
+            .WithFile(I18n("kato_en.json"), """{ "brief": "English" }""")
+            .WithFile(I18n("kato_pl.json"), """{ "brief": "Polski" }""");
+        var installation = new TestInstallation(files);
+        var scenery = Assert.Single(installation.Sceneries.LoadAll());
+        var translations = new SceneryTranslations(files, installation.Log);
+
+        translations.LoadFor(scenery, "Polski");
+
+        Assert.Equal("Polski", scenery.LocalizedDescription(translations));
+    }
+
+    [Fact]
+    public void Literal_text_and_unknown_keys_are_left_alone()
+    {
+        var installation = new TestInstallation();
+        var translations = new SceneryTranslations(installation.Files, installation.Log);
+
+        Assert.Equal("zwykły opis", translations.Translate("zwykły opis"));
+        Assert.Equal("@nieznany.klucz", translations.Translate("@nieznany.klucz"));
+        Assert.Equal("", translations.Translate(null));
+    }
+}