register-referentie/services/domain/Big.Tests/WithdrawRegistrationTests.cs

using Big.Application;
using Big.Domain;

namespace Big.Tests;

public class WithdrawRegistrationTests
{
    private static FakeUserTaskClient NoTasks() => new([]);

    [Fact]
    public async Task Withdrawing_marks_the_registration_ingetrokken_and_persists_it()
    {
        var store = new FakeRegistrationStore();
        var registration = Registration.Submit("123456782");
        store.Seed(registration);
        var handler = new WithdrawRegistration(store, NoTasks());

        await handler.HandleAsync(new WithdrawRegistrationCommand(registration.Id));

        var saved = await store.GetAsync(registration.Id);
        Assert.Equal(RegistrationStatus.Ingetrokken, saved!.Status);
        Assert.Equal(1, store.SaveCount);
    }

    [Fact]
    public async Task Withdrawing_cancels_the_open_beoordelen_task_via_its_execution()
    {
        var store = new FakeRegistrationStore();
        var registration = Registration.Submit("123456782");
        store.Seed(registration);
        var tasks = new FakeUserTaskClient([new BeoordelingTask("task-1", "exec-1", registration.Id)]);
        var handler = new WithdrawRegistration(store, tasks);

        await handler.HandleAsync(new WithdrawRegistrationCommand(registration.Id));

        // The withdrawal message is delivered to the Beoordelen task's execution, tripping the
        // boundary event that ends the process (ADR-0014).
        Assert.Equal("exec-1", tasks.WithdrawnExecutionId);
    }

    [Fact]
    public async Task Withdrawing_with_no_open_task_still_marks_ingetrokken()
    {
        // If the process has not parked at Beoordelen yet (or already ended), the withdrawal stands:
        // the aggregate is INGETROKKEN and nothing is cancelled.
        var store = new FakeRegistrationStore();
        var registration = Registration.Submit("123456782");
        store.Seed(registration);
        var tasks = NoTasks();
        var handler = new WithdrawRegistration(store, tasks);

        await handler.HandleAsync(new WithdrawRegistrationCommand(registration.Id));

        Assert.Equal(RegistrationStatus.Ingetrokken, (await store.GetAsync(registration.Id))!.Status);
        Assert.Null(tasks.WithdrawnExecutionId);
    }

    [Fact]
    public async Task Rejects_a_null_command_without_touching_the_store()
    {
        var store = new FakeRegistrationStore();
        var handler = new WithdrawRegistration(store, NoTasks());

        await Assert.ThrowsAsync<ArgumentNullException>(() => handler.HandleAsync(null!));
        Assert.Equal(0, store.SaveCount);
    }

    [Fact]
    public async Task Withdrawing_an_unknown_registration_throws()
    {
        var store = new FakeRegistrationStore();
        var handler = new WithdrawRegistration(store, NoTasks());

        var ex = await Assert.ThrowsAsync<InvalidOperationException>(
            () => handler.HandleAsync(new WithdrawRegistrationCommand(RegistrationId.New())));
        Assert.Contains("No registration", ex.Message);
        Assert.Equal(0, store.SaveCount);
    }

    [Fact]
    public async Task Re_withdrawing_an_already_ingetrokken_registration_is_idempotent()
    {
        var store = new FakeRegistrationStore();
        var registration = Registration.Submit("123456782");
        store.Seed(registration);
        var handler = new WithdrawRegistration(store, NoTasks());

        await handler.HandleAsync(new WithdrawRegistrationCommand(registration.Id));
        await handler.HandleAsync(new WithdrawRegistrationCommand(registration.Id));

        // The second withdrawal is a no-op: the aggregate is not persisted again.
        Assert.Equal(1, store.SaveCount);
        Assert.Equal(RegistrationStatus.Ingetrokken, (await store.GetAsync(registration.Id))!.Status);
    }
}