NUnit tests failed with FLuentValidation in ONion Architecture - asp.net-core

Question

Im trying to implement nunit tests with fluentvalidations, but it shows me a failed test and the message: FluentValidation.AsyncValidatorInvokedSynchronouslyException : Validator "AddVehicleCommandValidator" contains asynchronous rules but was invoked synchronously. Please call ValidateAsync rather than Validate.
In my test class I have a test method:
[Test]
public async Task ShouldRequireUniqueId()
{
var vehicle = await SendAsync(new AddVehicleCommand
{
Vehicle = new VehicleDto
{
Maker = "BMW",
Model = "M4",
UniqueId = "C1"
}
});
await SendAsync(new AddVehicleCommand
{
Vehicle = new VehicleDto
{
Maker = "BMW",
Model = "M4",
UniqueId = "C2"
}
});
var command = new AddVehicleCommand
{
Vehicle = new VehicleDto
{
Maker = "BMW",
Model = "M4",
UniqueId = vehicle.Data.UniqueId
}
};
var exception = FluentActions.Invoking(() => SendAsync(command))
.Should().ThrowAsync<ValidationException>();
}
Method SendAsync is a generic method for using MediatR and IPipelineBehavior:
public static async Task<TResponse> SendAsync<TResponse>(IRequest<TResponse> request)
{
using var scope = _scopeFactory.CreateScope();
var mediator = scope.ServiceProvider.GetService<IMediator>();
return await mediator.Send(request);
}
also I setup nessery things for registering services at onetimesetup method:
[OneTimeSetUp]
public static void RunBeforeAnyTests()
{
var builder = WebApplication.CreateBuilder();
var services = new ServiceCollection();
var startup = new Startup(_configuration);
startup.ConfigureServices(services);
services.AddSingleton(Mock.Of<IWebHostEnvironment>(w => w.ApplicationName == "VehicleReservation.WebApi" && w.EnvironmentName == "Development"));
_scopeFactory = services.BuildServiceProvider().GetService<IServiceScopeFactory>();
//_checkpoint = new Checkpoint();
}
So why this test fails? Tnx
UPDATE#1:
[Test]
public async Task ShouldRequireUniqueId()
{
var vehicle = await SendAsync(new AddVehicleCommand
{
Vehicle = new VehicleDto
{
Maker = "BMW",
Model = "M4",
UniqueId = "C1"
}
});
await SendAsync(new AddVehicleCommand
{
Vehicle = new VehicleDto
{
Maker = "BMW",
Model = "M4",
UniqueId = "C2"
}
});
var command = new AddVehicleCommand
{
Vehicle = new VehicleDto
{
Maker = "BMW",
Model = "M4",
UniqueId = vehicle.Data.UniqueId
}
};
var exception = await FluentActions.Awaiting(() => SendAsync(command))
.Should().ThrowAsync<ValidationException>();
}

Answer 1

The error message you describes an asynchronous validator is synchronously invoked. See https://docs.fluentvalidation.net/en/latest/async.html
So somewhere in your code you're blocking the validation.
FluentActions.Invoke takes an Action/Func<T>.
For async execution, use Awaiting
await FluentActions.Awaiting(() => SendAsync(command))
.Should().ThrowAsync<ValidationException>();