Phase 2-3: UI layout, theme switching, CRUD tools, process execution

- Phase 2: MainWindow 3-section layout (sidebar/content/log bar), Dark/Light theme with ThemeHelper, MainViewModel with ObservableProperty/RelayCommand, tool card filtering by search + category

- Phase 3: ToolEditWindow for add/edit tools, ProcessExecutionService (Process.Start + error handling), double-click + right-click context menu (run/edit), path browse dialog

- Bugfix: ContextMenu commands now use PlacementTarget.Tag binding (ContextMenu in separate visual tree)

- Bugfix: StaticResource converters moved to XAML before DataTemplate to fix XamlParseException on tool card render

- Bugfix: Pure filenames (no path separators) treated as PATH commands, not marked invalid

- Bugfix: RefreshData preserves SelectedCategory; Load() catches all exceptions; Save() wrapped in try-catch; auto-scroll log to newest entry

- Tests: xUnit project with 55 tests covering models, services, converters, and view models

PersonalToolBox.Tests/ViewModels/MainViewModelTests.cs

@@ -0,0 +1,186 @@
+using Moq;
+using Microsoft.Extensions.DependencyInjection;
+using PersonalToolBox.Models;
+using PersonalToolBox.Services;
+using PersonalToolBox.ViewModels;
+
+namespace PersonalToolBox.Tests.ViewModels;
+
+public class MainViewModelTests
+{
+    private readonly Mock<ILogService> _logServiceMock = new();
+    private readonly Mock<IDataService> _dataServiceMock = new();
+    private readonly Mock<IProcessExecutionService> _processServiceMock = new();
+    private readonly Mock<IServiceProvider> _serviceProviderMock = new();
+    private readonly AppConfig _config;
+
+    public MainViewModelTests()
+    {
+        _config = new AppConfig
+        {
+            Theme = "Dark",
+            Categories =
+            [
+                new() { Id = "1", Name = "开发工具" },
+                new() { Id = "2", Name = "系统工具" }
+            ],
+            Tools =
+            [
+                new() { Id = "t1", Name = "VS Code", CategoryId = "1", IsValid = true },
+                new() { Id = "t2", Name = "Postman", CategoryId = "1", IsValid = true },
+                new() { Id = "t3", Name = "任务管理器", CategoryId = "2", IsValid = true },
+                new() { Id = "t4", Name = "失效工具", CategoryId = "1", ExecutablePath = @"C:\missing.exe", IsValid = false }
+            ]
+        };
+
+        _dataServiceMock.Setup(d => d.Config).Returns(_config);
+    }
+
+    private MainViewModel CreateViewModel() =>
+        new(_logServiceMock.Object, _dataServiceMock.Object, _processServiceMock.Object, _serviceProviderMock.Object);
+
+    [Fact]
+    public void Constructor_LoadsCategories_IncludingAll()
+    {
+        var vm = CreateViewModel();
+
+        Assert.Equal(3, vm.Categories.Count);
+        Assert.Equal("全部", vm.Categories[0].Name);
+        Assert.Equal("开发工具", vm.Categories[1].Name);
+        Assert.Equal("系统工具", vm.Categories[2].Name);
+    }
+
+    [Fact]
+    public void Constructor_LoadsAllTools()
+    {
+        var vm = CreateViewModel();
+        Assert.Equal(4, vm.Tools.Count);
+    }
+
+    [Fact]
+    public void Default_CategoryIsAll_ShowsAllTools()
+    {
+        var vm = CreateViewModel();
+        Assert.Equal(4, vm.FilteredTools.Count);
+    }
+
+    [Fact]
+    public void SelectCategory_FiltersByCategory()
+    {
+        var vm = CreateViewModel();
+        vm.SelectedCategory = vm.Categories[1];
+        Assert.Equal(3, vm.FilteredTools.Count);
+    }
+
+    [Fact]
+    public void SearchText_FiltersByName()
+    {
+        var vm = CreateViewModel();
+        vm.SearchText = "post";
+        Assert.Single(vm.FilteredTools);
+        Assert.Equal("Postman", vm.FilteredTools[0].Name);
+    }
+
+    [Fact]
+    public void SearchText_CaseInsensitive()
+    {
+        var vm = CreateViewModel();
+        vm.SearchText = "POSTMAN";
+        Assert.Single(vm.FilteredTools);
+        Assert.Equal("Postman", vm.FilteredTools[0].Name);
+    }
+
+    [Fact]
+    public void SearchText_And_Category_FilterCombined()
+    {
+        var vm = CreateViewModel();
+        vm.SelectedCategory = vm.Categories[1];
+        vm.SearchText = "code";
+        Assert.Single(vm.FilteredTools);
+        Assert.Equal("VS Code", vm.FilteredTools[0].Name);
+    }
+
+    [Fact]
+    public void SearchText_Empty_ShowsAllInCategory()
+    {
+        var vm = CreateViewModel();
+        vm.SelectedCategory = vm.Categories[2];
+        vm.SearchText = "";
+        Assert.Single(vm.FilteredTools);
+        Assert.Equal("任务管理器", vm.FilteredTools[0].Name);
+    }
+
+    [Fact]
+    public void SearchText_NoMatch_ReturnsEmpty()
+    {
+        var vm = CreateViewModel();
+        vm.SearchText = "nonexistent";
+        Assert.Empty(vm.FilteredTools);
+    }
+
+    [Fact]
+    public void InvalidTools_StillAppearInFilteredResults()
+    {
+        var vm = CreateViewModel();
+        vm.SelectedCategory = vm.Categories[1];
+        var invalid = vm.FilteredTools.FirstOrDefault(t => t.Name == "失效工具");
+        Assert.NotNull(invalid);
+        Assert.False(invalid.IsValid);
+    }
+
+    [Fact]
+    public void ClearLogsCommand_CallsLogServiceClear()
+    {
+        var vm = CreateViewModel();
+        vm.ClearLogsCommand.Execute(null);
+        _logServiceMock.Verify(x => x.Clear(), Times.Once);
+    }
+
+    [Fact]
+    public void ToggleTheme_SwitchesDarkToLight()
+    {
+        var vm = CreateViewModel();
+        Assert.Equal("Dark", vm.CurrentTheme);
+        vm.ToggleThemeCommand.Execute(null);
+        Assert.Equal("Light", vm.CurrentTheme);
+    }
+
+    [Fact]
+    public void ToggleTheme_CallsSave()
+    {
+        var vm = CreateViewModel();
+        vm.ToggleThemeCommand.Execute(null);
+        _dataServiceMock.Verify(x => x.Save(), Times.Once);
+    }
+
+    [Fact]
+    public void ExecuteTool_CallsProcessService()
+    {
+        var vm = CreateViewModel();
+        var tool = vm.Tools[0];
+
+        vm.ExecuteToolCommand.Execute(tool);
+
+        _processServiceMock.Verify(x => x.Execute(tool), Times.Once);
+    }
+
+    [Fact]
+    public void ExecuteTool_Null_DoesNotCallProcessService()
+    {
+        var vm = CreateViewModel();
+        vm.ExecuteToolCommand.Execute(null);
+        _processServiceMock.Verify(x => x.Execute(It.IsAny<ToolItem>()), Times.Never);
+    }
+
+    [Fact]
+    public void RefreshData_ReloadsFromConfig()
+    {
+        var vm = CreateViewModel();
+
+        _config.Tools.Add(new ToolItem { Name = "NewTool" });
+
+        vm.RefreshData();
+
+        Assert.Equal(5, vm.Tools.Count);
+    }
+}