AccountingNext/Schaad.Accounting.Tests/TransactionRepositoryTestShould.cs

using NSubstitute;
using Schaad.Accounting.Interfaces;
using Schaad.Accounting.Models;
using Schaad.Accounting.Repositories;
using Shouldly;

namespace Schaad.Accounting.Tests;

public class TransactionRepositoryTestShould : IDisposable
{
    private readonly string dbDir;
    private readonly ISettingsService settingsService;
    private readonly IAccountRepository accountRepo;
    private readonly RepositoryCache cache;
    private readonly TransactionRepository sut;

    public TransactionRepositoryTestShould()
    {
        dbDir = Path.Combine(Path.GetTempPath(), "AccountingNext-tests-" + Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(dbDir);

        settingsService = Substitute.For<ISettingsService>();
        settingsService.GetDbPath().Returns(dbDir);
        settingsService.GetLastYearDbPath().Returns(Path.Combine(dbDir, "no-such-dir"));

        accountRepo = Substitute.For<IAccountRepository>();
        cache = new RepositoryCache();
        sut = new TransactionRepository(settingsService, cache, accountRepo);
    }

    public void Dispose()
    {
        if (Directory.Exists(dbDir))
        {
            Directory.Delete(dbDir, recursive: true);
        }
    }

    [Fact]
    public void PreserveValueWhenRoundTrippingNonFxTransaction()
    {
        accountRepo.GetAccount("chk").Returns(new Account { Id = "chk", Currency = "CHF" });
        accountRepo.GetAccount("groc").Returns(new Account { Id = "groc", Currency = "CHF" });

        sut.SaveTransaction(new Transaction
        {
            OriginAccountId = "chk",
            TargetAccountId = "groc",
            Value = 42m,
            Text = "Groceries",
            ValueDate = new DateTime(2026, 5, 10),
            BookingDate = new DateTime(2026, 5, 10)
        });

        var stored = sut.GetTransactionList().Single();
        var loaded = sut.GetTransaction(stored.Id);

        loaded.ShouldNotBeNull();
        loaded.Value.ShouldBe(42m);
        loaded.FxRate.ShouldBeNull(); // Non-FX transactions have FxRate cleared
    }

    [Fact]
    public void StoreInChfAndReturnInAccountCurrencyWhenTransactionIsFx()
    {
        // User enters 100 USD at rate 0.9 CHF/USD -> stored as 90 CHF; read back as 100 USD.
        accountRepo.GetAccount("chk").Returns(new Account { Id = "chk", Currency = "CHF" });
        accountRepo.GetAccount("usd").Returns(new Account { Id = "usd", Currency = "USD" });

        sut.SaveTransaction(new Transaction
        {
            OriginAccountId = "chk",
            TargetAccountId = "usd",
            Value = 100m,
            FxRate = 0.9m,
            Text = "USD transfer",
            ValueDate = new DateTime(2026, 5, 10),
            BookingDate = new DateTime(2026, 5, 10)
        });

        var stored = sut.GetTransactionList().Single();
        stored.Value.ShouldBe(90m); // stored in CHF

        var loaded = sut.GetTransaction(stored.Id);
        loaded.ShouldNotBeNull();
        loaded.Value.ShouldBe(100m); // display currency
        loaded.FxRate.ShouldBe(0.9m);
    }

    [Fact]
    public void ReturnNullWhenGettingUnknownTransactionId()
    {
        sut.GetTransaction("no-such-id").ShouldBeNull();
    }

    [Fact]
    public void NotMutateStoredValueWhenGettingFxTransactionTwice()
    {
        accountRepo.GetAccount("chk").Returns(new Account { Id = "chk", Currency = "CHF" });
        accountRepo.GetAccount("usd").Returns(new Account { Id = "usd", Currency = "USD" });

        sut.SaveTransaction(new Transaction
        {
            OriginAccountId = "chk",
            TargetAccountId = "usd",
            Value = 100m,
            FxRate = 0.9m,
            Text = "USD transfer",
            ValueDate = new DateTime(2026, 5, 10),
            BookingDate = new DateTime(2026, 5, 10)
        });

        var stored = sut.GetTransactionList().Single();
        var id = stored.Id;

        // Get twice; if Get mutated the stored entity, the second call would divide by FxRate again.
        var first = sut.GetTransaction(id);
        var second = sut.GetTransaction(id);

        first.ShouldNotBeNull();
        first.Value.ShouldBe(100m);
        second.ShouldNotBeNull();
        second.Value.ShouldBe(100m);
    }

    [Fact]
    public void RemoveTransactionWhenDeletingById()
    {
        accountRepo.GetAccount(Arg.Any<string>()).Returns(new Account { Currency = "CHF" });

        sut.SaveTransaction(new Transaction { OriginAccountId = "a", TargetAccountId = "b", Value = 1m, Text = "x", ValueDate = DateTime.Today });
        var id = sut.GetTransactionList().Single().Id;

        sut.DeleteTransaction(id);

        sut.GetTransactionList().ShouldBeEmpty();
    }
}