Pure Test

Pure Test is a free, zero-dependency JavaScript test runner built to span Node.js, Deno, Bun, Cloudflare Workers, and browsers. It is aimed at developers who prefer a compact, cross-runtime tool and are willing to control test state explicitly. The strongest case is a consistent CLI and API across runtimes; projects needing automatic isolation, snapshots, coverage, or a settled API should choose another runner.

Overview

Pure Test keeps its core deliberately small while covering the mechanics of ordinary unit testing. Its Apache-2.0 license and free distribution remove procurement barriers, and the same project can address server, edge, and browser-oriented JavaScript environments. That breadth is valuable for multi-runtime codebases, but the beta status means APIs may change, an important consideration for teams that prioritize long-term stability.

Key features

The API supplies test suites, assertions, lifecycle hooks, spies, fake timers, and retry and timeout controls. These features are enough for conventional unit and integration checks without adding dependencies. There is no module mocking, snapshot testing, built-in coverage, worker isolation, or configuration-file support. If those are central to your workflow, Pure Test will require supplementary tooling or custom conventions rather than providing a complete testing stack.

Its command-line interface offers multiple reporters, test filtering, file watching, sharding, and fail-fast execution. Sharding divides test files among CI jobs and exits cleanly when a shard receives no files, avoiding needless pipeline failures in uneven distributions. The runner does not isolate tests, so mutable state can leak from one case to another. Lifecycle hooks can contain that risk, but teams wanting automatic per-test isolation should look elsewhere.

TypeScript discovery is enabled with --ts on Node.js and automatic on Deno and Bun. A Deno adapter registers cases as Deno.test() calls, preserving Deno's native filtering and IDE-oriented workflows. Migration guidance for Jest and Vitest is included, with compatible common mock methods such as mockReturnValue and mock.calls; that can reduce rewrite effort, although it does not add the missing mocking, snapshot, or coverage systems.

Pricing

Pure Test is free software with no paid plans and no free trial. The sole plan, Apache-2.0 open-source software, costs free. There are no seat quotas, usage allowances, renewal charges, or paid tiers to weigh. It fits individual developers, open-source projects, and teams that can operate a beta dependency; organizations requiring commercial support terms or a fixed feature roadmap should account for that absence.

Platforms

Pure Test supports Linux, macOS, Windows, self-hosted deployments, and web use. Runtime coverage includes Node.js, Deno, Bun, Cloudflare Workers, and browsers. Installation through npm uses npm install @igorjs/pure-test --save-dev. Parallel execution is supported, with CLI sharding providing the clearest benefit for continuous-integration pipelines.

Who it's for

Choose Pure Test when one lightweight runner must cover several JavaScript runtimes, your CI benefits from sharding and clean empty-shard handling, and your team is comfortable enforcing state cleanup with hooks. It is also a sensible migration candidate for Jest or Vitest users whose needs fit the compatible common mock calls and whose projects do not depend on snapshots or coverage.

It is a poor match for suites that require process or worker isolation, module mocking, snapshot assertions, built-in coverage reports, or configuration files. The beta label and potentially changing APIs further favor experimental, internal, or fast-moving projects over large installations demanding conservative upgrades.

Pros and cons

Pros

• Cross-runtime reach: one runner targets Node.js, Deno, Bun, Cloudflare Workers, and browsers.
• Useful CI controls: sharding, fail-fast mode, filtering, and clean handling of empty shards support distributed pipelines.
• Focused core: suites, assertions, hooks, spies, fake timers, retries, and timeouts cover routine test work without dependencies.
• Migration assistance: Jest and Vitest guides plus common mock-method compatibility can shorten transitions.

Cons

• No isolation: shared state can contaminate later tests unless hooks enforce cleanup.
• Important omissions: module mocking, snapshots, coverage, worker isolation, and configuration files are intentionally excluded.
• Beta API: changing interfaces increase maintenance risk for teams seeking a stable foundation.

Alternatives

Vitest is a free, open-source option for Linux, macOS, web, and Windows when you want a mainstream alternative with no stated plan limits. QUnit suits projects seeking a free open-source framework distributed through CDN, npm, and Yarn across a particularly broad platform range. Karma is free and widely platformed, but it is deprecated and receives no new features or general bug fixes.

Web Test Runner is another free open-source choice for Linux, macOS, self-hosted, and web environments. Cucumber.js is free and installable as an npm development dependency when that project is the better fit. Jasmine provides a free route across Linux, macOS, web, and Windows, while Testem is a free MIT-licensed JavaScript test runner. Intern is a free option spanning Android, iOS, Linux, macOS, self-hosted, web, and Windows.

Verdict

Pure Test is best for developers who need a small, dependency-free runner across multiple JavaScript runtimes and value practical CLI sharding in CI. Choose it for focused suites where hooks can manage shared state and beta APIs are acceptable. Look elsewhere when isolation, snapshots, coverage, module mocking, or a mature, stable platform is a requirement.