Create Login page EditContext before async work

src/Aspire.Dashboard/Components/Pages/Login.razor.cs

@@ -38,6 +38,15 @@ public partial class Login : IAsyncDisposable
 
     protected override async Task OnInitializedAsync()
     {
+        // Create EditContext before awaiting. This is required to prevent an await in OnInitializedAsync
+        // triggering parameters being set on EditForm before EditContext is created.
+        // If that happens then EditForm errors that it requires an EditContext.
+        _formModel = new TokenFormModel();
+        EditContext = new EditContext(_formModel);
+        _messageStore = new(EditContext);
+        EditContext.OnValidationRequested += (s, e) => _messageStore.Clear();
+        EditContext.OnFieldChanged += (s, e) => _messageStore.Clear(e.FieldIdentifier);
+
         // If the browser is already authenticated then redirect to the app.
         if (AuthenticationState is { } authStateTask)
         {
@@ -48,12 +57,6 @@ protected override async Task OnInitializedAsync()
                 return;
             }
         }
-
-        _formModel = new TokenFormModel();
-        EditContext = new EditContext(_formModel);
-        _messageStore = new(EditContext);
-        EditContext.OnValidationRequested += (s, e) => _messageStore.Clear();
-        EditContext.OnFieldChanged += (s, e) => _messageStore.Clear(e.FieldIdentifier);
     }
 
     protected override async Task OnAfterRenderAsync(bool firstRender)

tests/Aspire.Dashboard.Components.Tests/Pages/LoginTests.cs

@@ -0,0 +1,73 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Aspire.Dashboard.Components.Tests.Shared;
+using Aspire.Dashboard.Model;
+using Bunit;
+using Microsoft.AspNetCore.Components.Authorization;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Localization;
+using Microsoft.Extensions.Logging;
+using Microsoft.FluentUI.AspNetCore.Components;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace Aspire.Dashboard.Components.Tests.Pages;
+
+[UseCulture("en-US")]
+public partial class LoginTests : TestContext
+{
+    private readonly ITestOutputHelper _testOutputHelper;
+
+    public LoginTests(ITestOutputHelper testOutputHelper)
+    {
+        _testOutputHelper = testOutputHelper;
+    }
+
+    [Fact]
+    public void Initialize_LongRunningAuthStateFunc_EditContextSet()
+    {
+        // Arrange
+        SetupLoginServices();
+
+        // This represents a long running auth state task.
+        var tcs = new TaskCompletionSource<AuthenticationState>(TaskCreationOptions.RunContinuationsAsynchronously);
+
+        // Act
+        var cut = RenderComponent<Components.Pages.Login>(builder =>
+        {
+            builder.Add(p => p.AuthenticationState, tcs.Task);
+        });
+
+        var instance = cut.Instance;
+        var logger = Services.GetRequiredService<ILogger<ConsoleLogsTests>>();
+        var loc = Services.GetRequiredService<IStringLocalizer<Resources.ConsoleLogs>>();
+
+        cut.WaitForState(() => instance.EditContext != null);
+    }
+
+    private void SetupLoginServices()
+    {
+        var version = typeof(FluentMain).Assembly.GetName().Version!;
+
+        JSInterop.SetupModule("/Components/Pages/Login.razor.js");
+
+        JSInterop.SetupModule(GetFluentFile("./_content/Microsoft.FluentUI.AspNetCore.Components/Components/Anchor/FluentAnchor.razor.js", version));
+
+        var textboxModule = JSInterop.SetupModule(GetFluentFile("./_content/Microsoft.FluentUI.AspNetCore.Components/Components/TextField/FluentTextField.razor.js", version));
+        textboxModule.SetupVoid("setControlAttribute", _ => true);
+
+        var loggerFactory = IntegrationTestHelpers.CreateLoggerFactory(_testOutputHelper);
+
+        Services.AddLocalization();
+        Services.AddSingleton<ILoggerFactory>(loggerFactory);
+        Services.AddSingleton<IDashboardClient>(new TestDashboardClient());
+        Services.AddSingleton<LibraryConfiguration>();
+        Services.AddSingleton<IKeyCodeService, KeyCodeService>();
+    }
+
+    private static string GetFluentFile(string filePath, Version version)
+    {
+        return $"{filePath}?v={version}";
+    }
+}