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/ExecutableLocatorTests.cs

@@ -0,0 +1,82 @@
+using StarterNG.Domain.Settings;
+using StarterNG.Tests.Fakes;
+
+namespace StarterNG.Tests;
+
+public class ExecutableLocatorTests
+{
+    private const string Elf = "\u007fELF binary";
+    private const string PortableExecutable = "MZ binary";
+
+    [Fact]
+    public void The_canonical_binary_is_preferred_over_other_candidates()
+    {
+        var files = new InMemoryFileSystem()
+            .WithExecutable(TestInstallation.At("eu07-dev"), Elf)
+            .WithExecutable(TestInstallation.At("eu07"), Elf);
+        var installation = new TestInstallation(files);
+
+        string resolved = installation.Executables.Resolve(new SimulatorSettings(), out var problem);
+
+        Assert.Equal(ExeProblem.None, problem);
+        Assert.EndsWith("eu07", resolved);
+    }
+
+    [Fact]
+    public void A_binary_for_the_other_platform_is_reported_as_such()
+    {
+        var files = new InMemoryFileSystem().WithExecutable(TestInstallation.At("eu07"), PortableExecutable);
+        var installation = new TestInstallation(files);
+
+        installation.Executables.Resolve(new SimulatorSettings(), out var problem);
+
+        Assert.Equal(ExeProblem.WrongPlatform, problem);
+    }
+
+    [Fact]
+    public void A_binary_without_the_execute_bit_is_reported_as_such()
+    {
+        var files = new InMemoryFileSystem().WithFile(TestInstallation.At("eu07"), Elf);
+        var installation = new TestInstallation(files);
+
+        installation.Executables.Resolve(new SimulatorSettings(), out var problem);
+
+        Assert.Equal(ExeProblem.NotExecutable, problem);
+    }
+
+    [Fact]
+    public void An_empty_installation_reports_the_canonical_name_as_missing()
+    {
+        var installation = new TestInstallation();
+
+        string resolved = installation.Executables.Resolve(new SimulatorSettings(), out var problem);
+
+        Assert.Equal(ExeProblem.NotFound, problem);
+        Assert.Equal("eu07", resolved);
+    }
+
+    [Fact]
+    public void A_manually_chosen_path_is_used_as_given()
+    {
+        var files = new InMemoryFileSystem().WithExecutable(TestInstallation.At("eu07-custom"), Elf);
+        var installation = new TestInstallation(files);
+        var settings = new SimulatorSettings { SelectExeAutomatically = false, ExecutablePath = "eu07-custom" };
+
+        string resolved = installation.Executables.Resolve(settings, out var problem);
+
+        Assert.Equal("eu07-custom", resolved);
+        Assert.Equal(ExeProblem.None, problem);
+    }
+
+    [Fact]
+    public void Data_files_beside_the_binary_are_never_offered_as_candidates()
+    {
+        var files = new InMemoryFileSystem()
+            .WithFile(TestInstallation.At("eu07.ini"), "width 1280")
+            .WithFile(TestInstallation.At("eu07.log"), "log")
+            .WithExecutable(TestInstallation.At("eu07"), Elf);
+        var installation = new TestInstallation(files);
+
+        Assert.Equal(new[] { "eu07" }, installation.Executables.ListCandidates());
+    }
+}