Entry Point
import { it, expect } from "@effect/vitest"| Feature | Description |
|---|---|
it.effect | Injects TestContext (includes TestClock) |
it.live | Uses live Effect environment (real clock, logging) |
it.scoped | Provides a Scope for resource management |
it.scopedLive | Combines scoped + live |
it.flakyTest | Retries flaky tests until success or timeout |
Basic Tests
import { it, expect } from "@effect/vitest"
import { Effect } from "effect"
it.effect("test success", () =>
Effect.gen(function* () {
const result = yield* Effect.succeed(42)
expect(result).toBe(42)
})
)Testing Failures with Exit
import { it, expect } from "@effect/vitest"
import { Effect, Exit } from "effect"
it.effect("test failure", () =>
Effect.gen(function* () {
const result = yield* Effect.exit(Effect.fail("oops"))
expect(result).toStrictEqual(Exit.fail("oops"))
})
)TestClock
it.effect provides TestClock starting at 0. Use it.live for real time.
import { it } from "@effect/vitest"
import { Clock, Effect, TestClock } from "effect"
it.effect("with simulated time", () =>
Effect.gen(function* () {
yield* TestClock.adjust("1000 millis")
const now = yield* Clock.currentTimeMillis
// now === 1000
})
)
it.live("with real time", () =>
Effect.gen(function* () {
const now = yield* Clock.currentTimeMillis
// now === actual system time
})
)Scoped Tests
Use it.scoped when your test acquires resources.
import { it } from "@effect/vitest"
import { Console, Effect } from "effect"
const resource = Effect.acquireRelease(
Console.log("acquire"),
() => Console.log("release")
)
it.scoped("manages resources", () =>
Effect.gen(function* () {
yield* resource // automatically released after test
})
)Flaky Tests
import { it } from "@effect/vitest"
import { Effect, Random } from "effect"
const flaky = Effect.gen(function* () {
if (yield* Random.nextBoolean) return yield* Effect.fail("random failure")
})
it.effect("retry until success", () =>
it.flakyTest(flaky, "5 seconds")
)Test Modifiers
it.effect.skip("skipped test", () => Effect.void)
it.effect.only("run only this", () => Effect.void)
it.effect.fails("expected to fail", () => Effect.fail("expected"))Logging
Logging is suppressed in it.effect. Enable with custom logger or it.live:
import { it } from "@effect/vitest"
import { Effect, Logger } from "effect"
it.effect("with logging", () =>
Effect.log("visible").pipe(Effect.provide(Logger.pretty))
)
it.live("logging enabled by default", () =>
Effect.log("visible")
)