maraphon-app/tests/Marathon.Application.Tests/UseCases/CompareStrategiesUseCaseTests.cs

using FluentAssertions;
using Marathon.Application.Abstractions;
using Marathon.Application.UseCases;
using Marathon.Domain.Backtesting;
using Marathon.Domain.Entities;
using Microsoft.Extensions.Logging.Abstractions;
using NSubstitute;

namespace Marathon.Application.Tests.UseCases;

public sealed class CompareStrategiesUseCaseTests
{
    private readonly ISavedStrategyRepository _strategies = Substitute.For<ISavedStrategyRepository>();
    private readonly IAnomalyRepository _anomalies = Substitute.For<IAnomalyRepository>();
    private readonly IEventRepository _events = Substitute.For<IEventRepository>();
    private readonly IResultRepository _results = Substitute.For<IResultRepository>();

    private CompareStrategiesUseCase CreateSut()
    {
        var backtest = new RunBacktestUseCase(_anomalies, _events, _results, NullLogger<RunBacktestUseCase>.Instance);
        return new CompareStrategiesUseCase(_strategies, backtest, NullLogger<CompareStrategiesUseCase>.Instance);
    }

    [Fact]
    public async Task Empty_When_NoPresets()
    {
        _strategies.ListAsync(Arg.Any<CancellationToken>()).Returns(Array.Empty<SavedStrategy>());

        (await CreateSut().ExecuteAsync(null)).Should().BeEmpty();
    }

    [Fact]
    public async Task RunsEachPreset_PreservingNameAndOrder()
    {
        _strategies.ListAsync(Arg.Any<CancellationToken>()).Returns(new[]
        {
            SavedStrategy.Create("Alpha", BacktestStrategy.Default),
            SavedStrategy.Create("Beta", BacktestStrategy.Default),
        });
        // No anomalies → each backtest returns a 0-bet result; events/results are never queried.
        _anomalies.ListAsync(Arg.Any<CancellationToken>()).Returns(Array.Empty<Anomaly>());

        var rows = await CreateSut().ExecuteAsync(null);

        rows.Select(r => r.Name).Should().ContainInOrder("Alpha", "Beta");
        rows.Should().OnlyContain(r => r.Result.BetsPlaced == 0);
    }
}