effect-facet-testing-testclock

name: effect-facet-testing-testclock description: Guidance for facet effect/testing/TestClock focused on APIs like make, layer, and setTime. Load after effect-skill-router when this facet is the primary owner.

Effect Facet testing/TestClock

Owned scope

• Owns only effect/testing/TestClock.
• Parent module: effect/testing.
• Source anchor: packages/effect/src/testing/TestClock.ts.

What it is for

• Module-specific APIs and usage patterns for Effect programs.

API quick reference

• make
• layer
• setTime
• State
• adjust
• Options
• withLive
• TestClock
• testClockWith
• Full API list: references/api-reference.md

How to use it

• Start with constructor-style APIs to build values/services before composing operations.
• Treat stateful APIs as synchronization boundaries and keep updates atomic.
• Use the reference docs to select the smallest API surface that solves your task.
• Validate behavior against existing tests before introducing new usage patterns.

Starter example

import { Effect, Fiber, Option, pipe } from "effect";
import { TestClock } from "effect/testing";
import * as assert from "node:assert";

Effect.gen(function* () {
  const fiber = yield* pipe(
    Effect.sleep("5 minutes"),
    Effect.timeout("1 minute"),
    Effect.forkChild,
  );
  yield* TestClock.adjust("1 minute");
  const result = yield* Fiber.join(fiber);
  assert.deepStrictEqual(result, Option.none());
});

Common pitfalls

• Prefer explicit, typed combinators over ad-hoc casting or unchecked assumptions.

Not covered here

• Sibling facets under the same parent are out of scope:
  • effect-facet-testing-fastcheck (effect/testing/FastCheck)
  • effect-facet-testing-testconsole (effect/testing/TestConsole)
  • effect-facet-testing-testschema (effect/testing/TestSchema)
• Parent module ownership belongs to effect-module-testing.

Escalate to

• effect-module-testing for parent module-wide workflows.
• effect-skill-router for cross-module routing and ownership checks.

Reference anchors

• Facet source: packages/effect/src/testing/TestClock.ts
• Parent tests: packages/effect/test/TestClock.test.ts
• Parent tests: packages/effect/test/Resource.test.ts
• Parent tests: packages/effect/test/Array.test.ts
• Parent tests: packages/effect/test/BigDecimal.test.ts
• Parent tests: packages/effect/test/Cache.test.ts
• Parent tests: packages/effect/test/Chunk.test.ts
• API details: references/api-reference.md
• Usage notes: references/usage-reference.md
• Ownership mapping: references/owner.md