/// <summary>
/// Adds an assertion that will be run after the request has completed, resolving a service from DI.
/// </summary>
/// <typeparam name="TService">The type of the service.</typeparam>
/// <param name="fixture">The fixture.</param>
/// <param name="assertion">The assertion.</param>
/// <returns></returns>
public static IMvcFunctionalTestFixture ShouldHaveProvidedServiceWhich <TService>(this IMvcFunctionalTestFixture fixture,
Func <TService, Task> assertion)
where TService : class =>
fixture.ShouldHaveServiceWhich(p => assertion(p.GetRequiredService <TService>()));