PostIt: fix grayed/inert file-row action buttons (wrong $parent binding)

The action buttons inside ItemsControl item templates (Télécharger /
Supprimer / Joindre on MyFiles; download/detach on the attachment
lists of BillingQueryDetailsPage and EstimateEditionPage) were bound
with $parent[vm:XxxViewModel].Cmd, which searches for an ancestor
CONTROL of type XxxViewModel — a viewmodel, not a control — so the
binding resolved to null and the Button stayed disabled (grayed) and
inert on click. Switch to the working CirclesPage/EstimateListPage
syntax: $parent[ContentPage].((vm:XxxViewModel)DataContext).Cmd.

Adds MyFilesPageHeadlessTests: mounts MyFilesPage via NavigationPage
+ Window.Show() and asserts each row button's Command is bound,
armed (CanExecute), and fires the API call on click. 136/136 pass.

Co-Authored-By: Claude Code <noreply@anthropic.com>

src/PostIt/PostIt.Tests/MyFilesPageHeadlessTests.cs

@@ -0,0 +1,208 @@
+using System.Net.Http;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Headless.XUnit;
+using Avalonia.VisualTree;
+using CommunityToolkit.Mvvm.Input;
+using PostIt.ViewModels;
+using PostIt.Views;
+using Yavsc.Api.Client;
+
+namespace PostIt.Tests;
+
+/// <summary>
+/// Headless UI coverage for the "Mes fichiers" page
+/// (<see cref="MyFilesPage"/>). The user reported that once a file
+/// is listed, "l'item est inerte au click, et ses boutons restent
+/// grisés, désactivés" — neither the row nor its action buttons
+/// (Télécharger / Supprimer) respond to a click.
+///
+/// <para>These tests mount a real <see cref="MyFilesPage"/> under
+/// the Avalonia headless platform with a stub
+/// <see cref="IYavscApiClient"/> that lists one file, then walk the
+/// realised visual tree to find the row's action buttons and
+/// assert the two things that would silently break and reproduce
+/// the "grayed / inert" symptom:</para>
+/// <list type="number">
+///   <item><description>The <c>Command</c> binding
+///   (<c>$parent[vm:MyFilesViewModel].DownloadFileCommand</c>)
+///   resolved to a non-null command — a null command leaves the
+///   button disabled (grayed) and click-silent.</description></item>
+///   <item><description>The command is <b>armed</b>
+///   (<c>CanExecute</c> true) for the listed file — an
+///   <c>AsyncRelayCommand</c> with
+///   <c>AllowConcurrentExecutions=false</c> (the
+///   <see cref="CommunityToolkit.Mvvm.Input.RelayCommandAttribute"/>
+///   default) disables itself while running; a button stuck
+///   "running" is exactly the grayed-and-inert report.</description></item>
+///   <item><description>Executing the command actually invokes the
+///   file download / delete on the API client — the row
+///   "activates" on click instead of being inert.</description></item>
+/// </list>
+/// <para>The OS save picker is absent under headless, so
+/// <c>FileSaveHelpers.SaveAsync</c> throws or cancels and the
+/// download command's <c>catch</c> sets an error status — but the
+/// API download is awaited <em>before</em> the picker, so the call
+/// is recorded regardless. We do not <c>await</c> the command's
+/// <c>ExecutionTask</c> to completion, to avoid blocking on the
+/// (platform-dependent) picker.</para>
+/// </summary>
+public class MyFilesPageHeadlessTests
+{
+    private static (MyFilesPage page, MyFilesViewModel vm, StubFsApi api) CreatePage()
+    {
+        var api = new StubFsApi();
+        var fsClient = new UserFilesApiClient(api, "https://blogs.example/api/v1/");
+        var vm = new MyFilesViewModel(fsClient);
+        var page = new MyFilesPage { DataContext = vm };
+        return (page, vm, api);
+    }
+
+    /// <summary>
+    /// Mount the page the way the app does — pushed onto a
+    /// <see cref="NavigationPage"/> shown in a <see cref="Window"/>
+    /// (a <see cref="ContentPage"/> realizes its content template via
+    /// the navigation host, cf. <c>RdvPageHeadlessTests</c>) — after
+    /// listing a single file by awaiting
+    /// <see cref="MyFilesViewModel.InitializeAsync"/>. Populating
+    /// <see cref="MyFilesViewModel.Files"/> before the first layout
+    /// pass lets the <c>ItemsControl</c> realise its item templates
+    /// under headless.
+    /// </summary>
+    private static async Task<(MyFilesPage page, MyFilesViewModel vm, StubFsApi api)> MountAsync()
+    {
+        var (page, vm, api) = CreatePage();
+        await vm.InitializeAsync();
+        var nav = new NavigationPage();
+        nav.PushAsync(page).GetAwaiter().GetResult();
+        var window = new Window { Content = nav };
+        window.Show();
+        // Let bindings / the ItemsControl item templates apply.
+        await Task.Delay(50);
+        return (page, vm, api);
+    }
+
+    /// <summary>
+    /// Find the first action button in a file row whose content
+    /// matches <paramref name="content"/>. The file rows live in an
+    /// <c>ItemsControl</c> DataTemplate (no <c>x:Name</c>), so we
+    /// walk the visual tree.
+    /// </summary>
+    private static Button? FindRowButton(MyFilesPage page, string content)
+        => page.GetVisualDescendants()
+            .OfType<Button>()
+            .FirstOrDefault(b => b.Content is string s && s == content);
+
+    [AvaloniaFact]
+    public async Task Download_button_on_a_file_row_is_bound_armed_and_fires_on_click()
+    {
+        var (page, vm, api) = await MountAsync();
+
+        // Sanity: the listing populated a file row.
+        Assert.NotEmpty(vm.Files);
+        Assert.NotNull(vm.Files[0].Id);
+
+        var downloadBtn = FindRowButton(page, "Télécharger");
+        Assert.NotNull(downloadBtn);
+        Assert.NotNull(downloadBtn!.Command);               // binding resolved (not grayed-via-null)
+        var param = downloadBtn.CommandParameter;
+        Assert.True(downloadBtn.Command!.CanExecute(param), // armed (not stuck running)
+            "Télécharger must be armed (CanExecute true) for a listed file.");
+
+        // Act: click → fire the command.
+        downloadBtn.Command.Execute(param);
+
+        // Assert: the row activated — the API download was invoked
+        // (it is awaited before the headless-absent save picker).
+        var recorded = false;
+        for (int i = 0; i < 40; i++)
+        {
+            if (api.Calls.Any(c => c.Method == HttpMethod.Get && c.Path == "fs/file/42"))
+            {
+                recorded = true;
+                break;
+            }
+            await Task.Delay(25);
+        }
+        Assert.True(recorded,
+            "Clicking Télécharger must invoke GET fs/file/{id} on the API client.");
+    }
+
+    [AvaloniaFact]
+    public async Task Delete_button_on_a_file_row_is_bound_armed_and_fires_on_click()
+    {
+        var (page, vm, api) = await MountAsync();
+
+        Assert.NotEmpty(vm.Files);
+
+        var deleteBtn = FindRowButton(page, "Supprimer");
+        Assert.NotNull(deleteBtn);
+        Assert.NotNull(deleteBtn!.Command);
+        var param = deleteBtn.CommandParameter;
+        Assert.True(deleteBtn.Command!.CanExecute(param),
+            "Supprimer must be armed (CanExecute true) for a listed file.");
+
+        deleteBtn.Command.Execute(param);
+
+        var recorded = false;
+        for (int i = 0; i < 40; i++)
+        {
+            if (api.Calls.Any(c => c.Method == HttpMethod.Delete))
+            {
+                recorded = true;
+                break;
+            }
+            await Task.Delay(25);
+        }
+        Assert.True(recorded,
+            "Clicking Supprimer must invoke DELETE fs/{path} on the API client.");
+    }
+
+    private sealed class StubFsApi : IYavscApiClient
+    {
+        public HttpClient Http { get; } = new();
+
+        public List<(HttpMethod Method, string Path, object? Body)> Calls { get; } = new();
+
+        private void Record(HttpMethod method, string path, object? body)
+            => Calls.Add((method, path, body));
+
+        public Task<T> CallAsync<T>(HttpMethod method, string path, object? body = null, CancellationToken ct = default)
+        {
+            Record(method, path, body);
+            if (typeof(T) == typeof(UserDirectoryDto))
+            {
+                var dir = new UserDirectoryDto
+                {
+                    UserName = "alice",
+                    Files = new[]
+                    {
+                        new FileEntryDto { Id = 42, Name = "note.txt", Size = 4 }
+                    }
+                };
+                return Task.FromResult((T)(object)dir);
+            }
+            return Task.FromResult(default(T)!);
+        }
+
+        public Task CallAsync(HttpMethod method, string path, object? body = null, CancellationToken ct = default)
+        {
+            Record(method, path, body);
+            return Task.CompletedTask;
+        }
+
+        public Task<T> CallAsync<T>(HttpMethod method, string path, Func<HttpContent> contentFactory, CancellationToken ct = default)
+            => CallAsync<T>(method, path, (object?)null, ct);
+
+        public Task CallAsync(HttpMethod method, string path, Func<HttpContent> contentFactory, CancellationToken ct = default)
+            => CallAsync(method, path, (object?)null, ct);
+
+        public Task<byte[]> DownloadAsync(HttpMethod method, string path, CancellationToken ct = default)
+        {
+            Record(method, path, null);
+            return Task.FromResult(new byte[] { 1, 2, 3, 4 });
+        }
+
+        public ValueTask DisposeAsync() => ValueTask.CompletedTask;
+    }
+}

src/PostIt/PostIt/Views/Activity/BillingQueryDetailsPage.axaml

@@ -113,13 +113,13 @@
                                                        TextTrimming="CharacterEllipsis" />
                                             <Button Grid.Column="1"
                                                     Content="Télécharger"
-                                                    Command="{Binding $parent[vm:BillingQueryDetailsPageViewModel].DownloadQueryAttachmentCommand}"
+                                                    Command="{Binding $parent[ContentPage].((vm:BillingQueryDetailsPageViewModel)DataContext).DownloadQueryAttachmentCommand}"
                                                     CommandParameter="{Binding}" />
                                             <Button Grid.Column="3"
                                                     Content="Détacher"
-                                                    Command="{Binding $parent[vm:BillingQueryDetailsPageViewModel].DetachQueryFileCommand}"
+                                                    Command="{Binding $parent[ContentPage].((vm:BillingQueryDetailsPageViewModel)DataContext).DetachQueryFileCommand}"
                                                     CommandParameter="{Binding}"
-                                                    IsVisible="{Binding $parent[vm:BillingQueryDetailsPageViewModel].CanAttach}" />
+                                                    IsVisible="{Binding $parent[ContentPage].((vm:BillingQueryDetailsPageViewModel)DataContext).CanAttach}" />
                                         </Grid>
                                     </Border>
                                 </DataTemplate>

src/PostIt/PostIt/Views/Activity/EstimateEditionPage.axaml

@@ -167,11 +167,11 @@
                                                        TextTrimming="CharacterEllipsis" />
                                             <Button Grid.Column="1"
                                                     Content="Télécharger"
-                                                    Command="{Binding $parent[vm:EstimateEditionPageViewModel].DownloadAttachmentCommand}"
+                                                    Command="{Binding $parent[ContentPage].((vm:EstimateEditionPageViewModel)DataContext).DownloadAttachmentCommand}"
                                                     CommandParameter="{Binding}" />
                                             <Button Grid.Column="3"
                                                     Content="Détacher"
-                                                    Command="{Binding $parent[vm:EstimateEditionPageViewModel].DetachFileCommand}"
+                                                    Command="{Binding $parent[ContentPage].((vm:EstimateEditionPageViewModel)DataContext).DetachFileCommand}"
                                                     CommandParameter="{Binding}" />
                                         </Grid>
                                     </Border>

src/PostIt/PostIt/Views/MyFiles/MyFilesPage.axaml

@@ -36,7 +36,7 @@
                     <ItemsControl.ItemTemplate>
                         <DataTemplate x:DataType="client:DirEntryDto">
                             <Button Content="📁 {Binding Name}"
-                                    Command="{Binding $parent[vm:MyFilesViewModel].OpenDirCommand}"
+                                    Command="{Binding $parent[ContentPage].((vm:MyFilesViewModel)DataContext).OpenDirCommand}"
                                     CommandParameter="{Binding}"
                                     HorizontalAlignment="Left"
                                     Margin="0,0,0,4" />
@@ -59,16 +59,16 @@
                                                TextWrapping="NoWrap" />
                                     <Button Grid.Column="1"
                                             Content="Joindre"
-                                            Command="{Binding $parent[vm:MyFilesViewModel].PickFileCommand}"
+                                            Command="{Binding $parent[ContentPage].((vm:MyFilesViewModel)DataContext).PickFileCommand}"
                                             CommandParameter="{Binding}"
-                                            IsVisible="{Binding $parent[vm:MyFilesViewModel].IsPickerMode}" />
+                                            IsVisible="{Binding $parent[ContentPage].((vm:MyFilesViewModel)DataContext).IsPickerMode}" />
                                     <Button Grid.Column="3"
                                             Content="Télécharger"
-                                            Command="{Binding $parent[vm:MyFilesViewModel].DownloadFileCommand}"
+                                            Command="{Binding $parent[ContentPage].((vm:MyFilesViewModel)DataContext).DownloadFileCommand}"
                                             CommandParameter="{Binding}" />
                                     <Button Grid.Column="5"
                                             Content="Supprimer"
-                                            Command="{Binding $parent[vm:MyFilesViewModel].DeleteFileCommand}"
+                                            Command="{Binding $parent[ContentPage].((vm:MyFilesViewModel)DataContext).DeleteFileCommand}"
                                             CommandParameter="{Binding}" />
                                 </Grid>
                             </Border>