Merge task branch for: fix(ui): DiffModal — Commit-Range ohne HeadCommit zeigt stillen Falsch-Diff

tests/ClaudeDo.Ui.Tests/ViewModels/DiffModalViewModelTests.cs

@@ -0,0 +1,54 @@
+using System.IO;
+using ClaudeDo.Localization;
+using ClaudeDo.Ui.Localization;
+using ClaudeDo.Ui.ViewModels.Modals;
+
+namespace ClaudeDo.Ui.Tests.ViewModels;
+
+public class DiffModalViewModelTests
+{
+    public DiffModalViewModelTests()
+    {
+        var dir = AppContext.BaseDirectory;
+        while (dir is not null && !Directory.Exists(Path.Combine(dir, "src", "ClaudeDo.Localization", "locales")))
+            dir = Path.GetDirectoryName(dir);
+        Loc.Current = new Localizer(
+            LocaleStore.Load(Path.Combine(dir!, "src", "ClaudeDo.Localization", "locales")), "en");
+    }
+
+    [Fact]
+    public async Task LoadAsync_CommitRange_NullHeadCommit_ShowsUnavailableState()
+    {
+        var vm = new DiffModalViewModel(null!)
+        {
+            WorktreePath = "/some/repo",
+            BaseRef = "abc123",
+            HeadCommit = null,
+            FromCommitRange = true,
+        };
+
+        await vm.LoadAsync();
+
+        Assert.Empty(vm.Files);
+        Assert.NotNull(vm.StatusMessage);
+        Assert.Contains("no longer available", vm.StatusMessage, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task LoadAsync_CommitRange_NullBaseRef_ShowsUnavailableState()
+    {
+        var vm = new DiffModalViewModel(null!)
+        {
+            WorktreePath = "/some/repo",
+            BaseRef = null,
+            HeadCommit = "def456",
+            FromCommitRange = true,
+        };
+
+        await vm.LoadAsync();
+
+        Assert.Empty(vm.Files);
+        Assert.NotNull(vm.StatusMessage);
+        Assert.Contains("no longer available", vm.StatusMessage, StringComparison.OrdinalIgnoreCase);
+    }
+}