如何在 bunit Blazor 組件單元測試中注入 NavigationManager

Question

從單元測試注入時出現此錯誤。

System.InvalidOperationException: ''NavigationManagerProxy' has not been initialized.'

我的代碼：

Services.AddSingleton<NavigationManager>(Mock.Of<NavigationManager>());         

Answer 1

我將這個類用於我的單元測試：

internal class TestNav : NavigationManager
{
    public TestNav()
    {
        Initialize("https://unit-test.example/", "https://unit-test.example/");
    }

    protected override void NavigateToCore(string uri, bool forceLoad)
    {
        NotifyLocationChanged(false);
    }
}

然后在測試中設置如下：

Services.AddSingleton<NavigationManager>(new TestNav());

Answer 2

在為Blazing Pizza Workshop編寫測試時，我們使用了這個（類似於@Akinzekeel 的代碼）：

    public class FakeNavigationManager : NavigationManager
    {
        private readonly ITestRenderer renderer;

        public FakeNavigationManager(ITestRenderer renderer)
        {
            Initialize("http://localhost/", "http://localhost/");
            this.renderer = renderer;
        }

        protected override void NavigateToCore(string uri, bool forceLoad)
        {
            Uri = ToAbsoluteUri(uri).ToString();

            renderer.Dispatcher.InvokeAsync(
                () => NotifyLocationChanged(isInterceptedLink: false));
        }
    }

測試如下所示：

@inherits TestContext
@code {
    private NavigationManager navigationManager; 

    public MainLayoutTests()
    {
        Services.AddSingleton<NavigationManager, FakeNavigationManager>();
        navigationManager = Services.GetService<NavigationManager>();        
    }

    [Fact]
    public void MyOrdersNavigationItem_Is_Marked_As_Active_When_Viewing_MyOrdersPage()
    {
        var cut = Render(@<MainLayout />);

        navigationManager.NavigateTo("myorders");

        cut.Find("a[href=myorders]")
            .ClassList
            .Should()
            .Contain("active");
    }
}

我還沒有測試過各種場景，但這至少在這種情況下似乎有效。