node:test

Node.js test module, resolvable via both ESM import and CommonJS require (as node:test). It is implemented as a guest-JavaScript test runner layered over Elide's node:assert: it builds a test tree, executes it with hooks and subtests, and reports results in nested TAP.

javascript

import test, { describe, it } from "node:test";

test("addition", (t) => {
  t.assert.strictEqual(1 + 1, 2);
});

describe("math", () => {
  it("multiplies", (t) => {
    t.assert.strictEqual(2 * 3, 6);
  });
});

Implemented surface

Defining tests

Export	Description
`test(name?, options?, fn)` / `it(...)`	Define a test. `it` is an alias of `test`.
`describe(name?, options?, fn)` / `suite(...)`	Group tests into a suite. `suite` is an alias of `describe`.
`.skip` / `.todo` / `.only`	Modifiers on `test` / `it` / `describe` (e.g. `test.skip(...)`); `—test-only` filtering is honoured.

Hooks

before, after, beforeEach, and afterEach register lifecycle hooks at the top level or inside a describe / suite, and are also available per-test through the test context.

Test context (`t`)

The function passed to a test receives a context object t:

Member	Description
`t.assert.*`	The `node:assert` surface, bound to the running test.
`t.test(...)`	Define a nested subtest.
`t.before` / `t.after` / `t.beforeEach` / `t.afterEach`	Per-test hooks.
`t.diagnostic(msg)`	Emit a TAP diagnostic line.
`t.plan(count)`	Declare the expected number of assertions.
`t.skip([msg])` / `t.todo([msg])`	Mark the running test skipped / todo.
`t.mock`	The test-scoped mock tracker (see below).
`t.signal`	An `AbortSignal` tied to the test's timeout and lifetime.

Mocking (`mock`)

The mock export (and t.mock) tracks and restores mocks:

Member	Description
`mock.fn([original][, impl][, options])`	Create a mock function with call tracking.
`mock.method(obj, name[, impl][, options])`	Replace a method with a mock.
`mock.getter` / `mock.setter` / `mock.property`	Mock accessors / data properties.
`mock.timers`	Fake-timer controller (`enable` / `tick` / `reset` / …).
`mock.reset()` / `mock.restoreAll()`	Reset call state / restore all mocks.

test.assert exposes the same assertion surface at module scope.

Not implemented

The following are exported (or present on the context) but throw ERR_METHOD_NOT_IMPLEMENTED when called:

run() — the programmatic runner entry point.
t.assert.snapshot(...) / t.assert.fileSnapshot(...), and the test.snapshot.* configuration setters (snapshot testing).
mock.module(...) — module mocking.