@reventlessdev/rescript-jest

⚠️ Alpha. APIs and on-disk formats can change without notice between releases. Pin exact versions and expect breaking changes.

Direct ReScript bindings to Jest's global APIs, with throwing expect and native async test bodies.

This is the single, shared replacement for the per-package Jest binding modules the monorepo used to hand-roll (AsyncTest, TestHelpers, JestBind). ReScript module visibility is per-package, so each package that needed async-capable, throwing-expect bindings re-wrote them; this package consolidates that surface at the bottom of the dependency graph.

Why not @glennsl/rescript-jest?

glennsl's assertion model is deferred by design: expect |> toBe builds a value that only executes when it is returned from the test body (one affirmed assertion per test). A mid-test assertion whose result is not returned is silently inert — a forgotten return passes green. Its testPromise also discards the returned Promise, so async tests in a describe block race.

These bindings call Jest's globals directly: every expect(...)->toBe(...) executes at its line, and async () => ... test bodies are awaited.

Usage

open JestGlobals

describe("widget", () => {
  testSync("adds", () => {
    expect(1 + 1)->toBe(2)
  })

  test("loads async", async () => {
    let v = await fetchValue()
    expect(v)->toEqual(expected)
  })
})

test registers an async test; testSync a synchronous one. beforeAll / afterAll are synchronous; beforeAllAsync / afterAllAsync await a returned promise. Matchers are available both flat and under module Expect.

Links

• 📚 Documentation — docs.reventless.dev
• 📦 Repository — ReventlessDev/reventless-core
• 📋 Changelog

License

Apache-2.0