Trax.Core.Testing 1.8.0

Trax.Core

Part of Trax: business logic you can call, schedule, or serve as an API, with every run recorded in your Postgres. Docs · Getting started · All repos

Trax.Core defines trains for .NET. A train is a typed pipeline of small steps (junctions): when a junction throws, the rest are skipped and the train returns the exception. It has no database and no DI container, and the other Trax layers build on it.

Install

dotnet add package Trax.Core
dotnet add package Trax.Core.Testing   # optional: architecture-guard fixtures for your NUnit tests

Trax.Core targets .NET 10.

Example

using LanguageExt;
using Trax.Core.Junction;
using Trax.Core.Train;

public record CreateUserRequest(string Email);
public record User(Guid Id, string Email);

public class ValidateEmailJunction : Junction<CreateUserRequest, Unit>
{
    public override Task<Unit> Run(CreateUserRequest input)
    {
        if (!input.Email.Contains('@'))
            throw new ArgumentException($"'{input.Email}' is not an email address");
        return Task.FromResult(Unit.Default);
    }
}

public class CreateUserJunction : Junction<CreateUserRequest, User>
{
    public override Task<User> Run(CreateUserRequest input) =>
        Task.FromResult(new User(Guid.NewGuid(), input.Email));
}

public class CreateUserTrain : Train<CreateUserRequest, User>
{
    protected override Task<Either<Exception, User>> Junctions() =>
        Chain<ValidateEmailJunction>()
            .Chain<CreateUserJunction>()
            .Resolve();
}

Run it with RunEither, which never throws, and read the Either:

Either<Exception, User> result = await new CreateUserTrain().RunEither(new CreateUserRequest("ada@example.com"));

string message = result.Match(
    Right: user => $"created {user.Id}",
    Left: ex => $"failed: {ex.Message}");

If ValidateEmailJunction throws, CreateUserJunction never runs and result holds the exception. Run returns the User directly and rethrows instead.

Where this fits

Trax is split into layers, one repo each. Take the ones you need; the trains you wrote do not change. You are here: Trax.Core.

Docs live in Trax.Docs and are published at traxsharp.net/docs.

Contributing

Read AGENTS.md before changing code. Report vulnerabilities privately as described in SECURITY.md.

License

MIT. There is no commercial edition, and there will not be one.

Trax is an independent open-source project and is not affiliated with the Utah Transit Authority, Trax Retail, or any other organization using the Trax name.