bunit-testing

bUnit Test Authoring

This skill covers writing new bUnit v2 component tests for the BlazorWebFormsComponents library.

Not for migration. If you need to migrate existing tests from bUnit beta to v2, use the bunit-test-migration skill instead.

Test Infrastructure

BlazorWebFormsTestContext

All BWFC component tests should inherit from BlazorWebFormsTestContext, which extends bUnit's BunitContext with pre-registered services:

public abstract class BlazorWebFormsTestContext : BunitContext
{
    // Pre-configured:
    // - JSInterop.Mode = JSRuntimeMode.Loose
    // - LinkGenerator (mocked)
    // - IHttpContextAccessor (mocked)
    // - IWebHostEnvironment (mocked with temp paths)
    // - IMemoryCache
    // - CacheShim, ServerShim, ClientScriptShim
    // - ILogger<T> (with optional xUnit output)
}

This base class ensures components that depend on WebFormsPageBase shims can render without additional setup.

Test File Location

Tests are .razor files organized by component name:

src/BlazorWebFormsComponents.Test/
├── Button/
│   ├── Click.razor
│   ├── Enabled.razor
│   └── Style.razor
├── GridView/
│   ├── Selection.razor
│   ├── Sorting.razor
│   └── Paging.razor
├── Validations/
│   └── SetFocusOnErrorTests.razor
└── ...

Test Naming Convention

ComponentName_Scenario_ExpectedBehavior

Examples:

• Button_Click_InvokesHandler
• GridView_WithDataSource_RendersRows
• RequiredFieldValidator_BlankInput_DisplaysError

Writing Tests

Basic Pattern

@inherits BlazorWebFormsTestContext

@code {
    [Fact]
    public void Button_Click_InvokesHandler()
    {
        // Arrange
        var clicked = false;
        var cut = Render(@<Button OnClick="() => clicked = true">Submit</Button>);

        // Act
        cut.Find("input").Click();

        // Assert
        clicked.ShouldBeTrue();
    }
}

Testing Component Properties

@code {
    [Fact]
    public void Label_Text_RendersInSpan()
    {
        var cut = Render(@<Label Text="Hello World" />);

        cut.Find("span").TextContent.ShouldBe("Hello World");
    }

    [Fact]
    public void TextBox_Visible_False_RendersNothing()
    {
        var cut = Render(@<TextBox Visible="false" />);

        cut.FindAll("input").Count.ShouldBe(0);
    }
}