Turmoil

This is very experimental

Add hardship to your tests.

Turmoil is a framework for testing distributed systems. It provides deterministic execution by running multiple concurrent hosts within a single thread. It introduces "hardship" into the system via changes in the simulated network and filesystem. Both can be controlled manually or with a seeded rng.

Quickstart

Add this to your Cargo.toml.

[dev-dependencies]
turmoil = "0.7"

See crate documentation for simulation setup instructions.

Examples

/tests for TCP, UDP, and filesystem.
gRPC using tonic and hyper.
axum

Filesystem Simulation (unstable)

Requires the unstable-fs feature.

[dev-dependencies]
turmoil = { version = "0.7", features = ["unstable-fs"] }

Turmoil provides simulated filesystem types for crash-consistency testing:

use turmoil::fs::shim::std::fs::OpenOptions;
use turmoil::fs::shim::std::os::unix::fs::FileExt;

let file = OpenOptions::new()
    .read(true)
    .write(true)
    .create(true)
    .open("/data/db")?;

file.write_all_at(b"data", 0)?;
file.sync_all()?;  // Data now durable, survives sim.crash()

Each host has isolated filesystem state. Use Builder::fs_sync_probability() to configure random sync behavior for testing crash recovery.

License

This project is licensed under the MIT license.

Contribution