在异步Nancy路由中测试取消处理代码？

Question

在Nancy中测试异步路由时，如何在单元测试中模拟取消条件？

在查看此question on the source of Nancy's cancellation tokens时，尚未确定如何触发取消。知道这可能对此有所帮助，但即使没有这方面的知识，Browser或Browser.Get上有一些方法可以强制IsCancellationRequested在提供的异步取消令牌上成立吗？

这是一个非常简化的异步路由，其中​​我有一个取消路径和不完整的测试我希望将该取消逻辑作为目标。

Get["/somethingasync", runAsync: true] = async (parameters, cancellationToken) => {
    await DoSomethingSlow();
    // Check for cancellation before doing anything else slow
    if (cancellationToken.IsCancellationRequested) {
        // TODO: How do I force this path to be taken in a test?
        return "cancelled";
    }
    await DoSomethingElseSlow();
    return "success";
};

[Test]
public void Cancelled_request_should_return_cancelled ()
{
    // Given
    var browser = new Browser (with => {
        with.Module<SomeModuleContainingAboveRoute> ();
    });

    // TODO: What goes here to make the following `Get` take the
    //       cancellation path in the above route?

    // When
    var result = browser.Get ("/somethingasync", with => {
        with.HttpRequest ();
    });

    // Then
    Assert.AreEqual ("cancelled", result.Body.AsString ());
}