test-isolation

Scoped testing framework for Go with path isolation — parallel by default, zero dependencies, assertion-library agnostic

Custom Jest environment that detects async leaks within tests and prevents flaky test failures.

Run marked pytest tests in grouped subprocesses (cross-platform).

Give every concurrent Laravel test run its own databases by claiming a machine-unique lane for each process

Per-process Application.get_env overrides, so config-dependent Elixir tests can stay async: true – plus an overridable clock and the same machinery for ambient values of your own.

Uncompromising test isolation: your tests structurally cannot touch your real files, secrets, or git identity -- First-class support for Go, Python with pytest, and TypeScript with Node

Class-scoped, transaction-isolated test fixtures for Laravel — build factory data once per test class, share it across tests with per-test rollback.

Run Spring test classes across Gradle workers with shared Testcontainers, isolated PostgreSQL and Redis databases, and context reuse.

Detect RSpec examples that leak global state, resources, time travel, randomness, or filesystem changes.

Find out which real files your test suite writes to - including from subprocesses your other guards cannot see