Testing

The package has no built-in fake and no in-memory Redis. There are two options: run a real disposable server, or replace the Redis service with a stub.

Testing against a disposable serverCopy Anchor Link

Run Redis or Valkey in a container and build the layer from its address. The package's own end-to-end tests do this with Testcontainers.

Example (A Layer for a Server Started by Your Test Setup)

import { Effect } from "effect";
import { Redis } from "@effect-kit/redis";
import { RedisNode } from "@effect-kit/redis/node";

// Started by your test setup, for example: docker run --rm -p 6379:6379 redis:7.4
const RedisTest = RedisNode.layer({ url: "redis://localhost:6379", database: 15 });

export const countVisits = Effect.gen(function* () {
  const redis = yield* Redis;
  yield* redis.del(["test:visits"]);
  yield* redis.incr("test:visits");
  return yield* redis.incr("test:visits");
}).pipe(Effect.provide(RedisTest));

// Output: 2n

Use a database number or key prefix that only tests touch, and delete what a test creates. The layer connects when it is built, so a missing server fails the test at setup, before the first command.

The package tests against Redis 6.2.19, 7.2.11, 7.4.6 and 8.10.2, and Valkey 7.2.11, 8.0.3 and 9.1.2. Pick the version your production uses.

Stubbing the serviceCopy Anchor Link

Redis is a plain service, so Layer.succeed can replace it. Cast a partial implementation, and make anything you did not stub fail loudly.

Example (A Stub That Answers One Command)

import { Effect, Layer, Option } from "effect";
import { Redis } from "@effect-kit/redis";
import type { RedisClient } from "@effect-kit/redis";

const RedisStub = Layer.succeed(Redis, {
  get: (key: string) => Effect.succeed(key === "greeting" ? Option.some("hello") : Option.none()),
} as unknown as RedisClient);

export const greet = Effect.gen(function* () {
  const redis = yield* Redis;
  return yield* redis.get("greeting");
}).pipe(Effect.provide(RedisStub));

A stub checks your code's logic, not Redis behavior. It cannot tell you that a key expires, that a pipeline fails halfway, or that a command is rejected by the server.

Testing timingCopy Anchor Link

@effect/vitest provides it.effect, which runs with a TestClock, and it.live, which uses the real clock. Use it.live for anything that talks to a real server.

Example (A Live Test Against a Server)

import { expect, it } from "@effect/vitest";
import { Effect } from "effect";
import { Redis } from "@effect-kit/redis";
import { RedisNode } from "@effect-kit/redis/node";

const RedisTest = RedisNode.layer({ url: "redis://localhost:6379", database: 15 });

it.live("increments a counter", () =>
  Effect.gen(function* () {
    const redis = yield* Redis;
    yield* redis.del(["test:counter"]);

    expect(yield* redis.incr("test:counter")).toBe(1n);
  }).pipe(Effect.provide(RedisTest)),
);