Would you use a bUnit-like test library for native .NET MAUI views?

[jaimeatsherpa]

Would you use a bUnit-like test library for native .NET MAUI views?

I’m experimenting with a small library for testing native .NET MAUI ContentView / ContentPage instances in a way that sits between:

• ViewModel unit tests
• full UI tests with Appium.

Appium is the official/main path for MAUI UI automation and is great for real end-to-end validation, but it’s also heavier and slower because it drives the actual app on device/desktop.

What I’m exploring instead is something closer in spirit to bUnit for Blazor: render a view in a test, inspect the resulting tree, find controls, and assert on their state. bUnit is useful precisely because it provides fast component-level tests instead of requiring full browser automation for everything.

Based on something like:

<ContentView xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="App.LoginView">
    <VerticalStackLayout Spacing="12">
        <Entry
            x:Name="EmailEntry"
            AutomationId="EmailEntry"
            Text="{Binding Email}"
            IsEnabled="{Binding CanSubmit}" />

        <Button
            x:Name="SubmitButton"
            AutomationId="SubmitButton"
            Text="Sign in"
            IsEnabled="{Binding CanSubmit}" />

        <ActivityIndicator
            x:Name="LoadingIndicator"
            AutomationId="LoadingIndicator"
            IsRunning="{Binding IsLoading}"
            IsVisible="{Binding IsLoading}" />

        <Label
            x:Name="ErrorLabel"
            AutomationId="ErrorLabel"
            Text="{Binding ErrorMessage}"
            IsVisible="{Binding ShowError}" />
    </VerticalStackLayout>
</ContentView>

The kind of API I have in mind is:

using var ctx = MauiTestContext.Create();

var rendered = ctx.Render<LoginView>()
    .ApplyViewModel(new LoginViewModel
    {
        Email = "john@example.com",
        IsLoading = true
    });

Assert.Equal("john@example.com",
    rendered.FindByAutomationId<Entry>("EmailEntry").Text);

Assert.False(
    rendered.FindByAutomationId<Button>("SubmitButton").IsEnabled);

This would not replace Appium. It would be for things like:

• checking whether controls exist
• verifying IsVisible, IsEnabled, Text
• validating state-driven XAML output
• maybe running an optional headless layout pass for width/height assertions

So the value would be:

• much faster than E2E
• much less setup than Appium
• more UI-focused than plain ViewModel tests

Would this be useful to you?

The main question I’m trying to answer is whether MAUI is missing a middle layer:

ViewModel tests → component/page tests → Appium tests

[stephenquan]

CommunityToolkit.Maui uses xUnit and CommunityToolkit.Maui.Markup uses nUnit. In both of those cases they add a base test harness that mocks a .NET MAUI application and the corresponding dispatcher so that .NET MAUI components can be tested. I'm not familiar with bUnit but you will need to solve the same problem. If you don't have those things mocked, then, you will not be able to satisfactory test any .NET MAUI component.

Help vote up CommunityToolkit/Maui#3040 so that the general .NET MAUI developer community can reuse the same test harness.