Rask.Testing 0.19.0

Rask.Testing

Unit-test Rask components — render a component to HTML, invoke its event handlers, and assert on the re-rendered markup. No browser, no server, no WebSocket.

using Rask.Testing;

public sealed class Counter : Component
{
    private int _count;
    protected override Component? Render() =>
        Button(Type: "button", OnClick: () => _count++)[$"Count: {_count}"];
}

[Fact]
public async Task Clicking_increments()
{
    var page = RaskTest.Render(new Counter());
    Assert.Contains("Count: 0", page.Html);

    await page.ClickAsync();               // dispatch the click handler + re-render
    Assert.Contains("Count: 1", page.Html);
}

API

• RaskTest.Render(component, services?) → a RenderedComponent. Renders the component with its event handlers wired; pass an IServiceProvider when the component constructor-injects services.
• RaskTest.Render(factory, services?) — same, but the factory runs on every render, so the tree is rebuilt from your current state each time. Use it whenever a re-render should see changed props: RaskTest.Render(() => Form(model)[Input(() => model.Name)]). The component overload renders one fixed instance, so a tree you build at the call site keeps the values it was built with.
• RenderedComponent.Html — the current markup, reflecting the latest state.
• .ClickAsync(json?) / .InvokeAsync(handlerId, json?) — dispatch a handler (optionally with a JSON event payload like "{\"value\":\"hi\"}" for an input) and re-render; returns the new Html.
• .HandlerId(domEvent) — the handler id wired to "click"/"input"/"change"/"submit"/…
• .Attr(name) — the first name="…" attribute value in the current Html.
• .HandlerIds(domEvent) / .Attrs(name) — every match, in document order. Index these to target one of several same-event elements: await page.InvokeAsync(page.HandlerIds("click")[1]).
• Markup.Attr(html, name) / Markup.Attrs(html, name) — the same lookups over any HTML string.
• .TryInvokeAsync(handlerId, json?) — dispatch only if the id is still live; returns false rather than throwing, so you can assert a handler is gone.
• .Instance — the component object you passed in, for asserting its state directly.
• .Render() — re-render after mutating external state the component reads.
• TestJSRuntime — an IJSRuntime that records calls and returns canned values, for components that inject IJSRuntime. Register it in the provider, then assert with .ArgsFor(id) / .Calls / .CallCount(id); configure with .SetResponse(id, value) / .SetException(id, ex).
• RaskTest.EditContextProbe(capture) — placed inside a Form's children, hands you the form's EditContext so you can assert validation state (GetValidationMessages, IsModified, IsValidating) that never appears in the markup.

Install

Reference from your test project. Rask.Core comes transitively from the app under test (via its Rask.Server / Rask.Wasm reference), so you don't reference it directly.

dotnet add <YourApp>.Tests package Rask.Testing

See the testing guide for forms, validation, and DI examples.