Module dst 

DST - Deterministic Simulation Testing

TigerBeetle/FoundationDB-style deterministic simulation testing framework.

Philosophy

“If you’re not testing with fault injection, you’re not testing.”

Usage

use umi_memory::dst::{Simulation, SimConfig, FaultConfig, FaultType};

#[tokio::test]
async fn test_storage_survives_faults() {
    let sim = Simulation::new(SimConfig::with_seed(42))
        .with_fault(FaultConfig::new(FaultType::StorageWriteFail, 0.1));

    sim.run(|env| async move {
        env.storage.write("key", b"value").await?;
        env.clock.advance_ms(1000);
        let result = env.storage.read("key").await?;
        assert_eq!(result, Some(b"value".to_vec()));
        Ok(())
    }).await.unwrap();
}

Run with explicit seed for reproducibility:

DST_SEED=12345 cargo test

Structs

DeterministicRng

A deterministic random number generator.

FaultConfig

Configuration for a specific fault.

FaultInjector

Fault injector for simulation testing.

FaultInjectorBuilder

Builder for FaultInjector (Kelpie pattern).

NetworkMessage

A network message in flight.

PropertyTest

Property-based test runner.

PropertyTestFailure

Details of a property test failure.

PropertyTestResult

Result of a property test run.

SimClock

A simulated clock for deterministic testing.

SimConfig

Configuration for a simulation run.

SimEnvironment

Environment provided to simulation tests.

SimLLM

Simulated LLM for deterministic testing.

SimNetwork

Simulated network for DST.

SimStorage

Simulated storage for DST testing.

Simulation

DST simulation harness.

TimeAdvanceConfig

Configuration for time advancement during property tests.

Enums

FaultType

Types of faults that can be injected.

LLMError

Errors from LLM operations.

NetworkError

Network errors.

StorageError

Storage errors.

Traits

PropertyTestable

Trait for systems that can be property-tested.

Functions

create_simulation

Create a simulation with optional seed.

run_property_tests

Run multiple property tests with different seeds.

test_seeds

Generate a set of test seeds including edge cases.

Type Aliases

StorageReadError

Read-specific error alias.

StorageWriteError

Write-specific error alias.