chore(redis): support ioredis-mock for unit testing (#5817)

## Summary

Add built-in support for using
[ioredis-mock](https://github.com/stipsan/ioredis-mock) in unit tests,
and document how to configure it.

## Problem

When using `config.redis.Redis = RedisMock` (ioredis-mock) for unit
testing, the app hangs on startup because:

1. `ioredis-mock` emits the `ready` event synchronously during
construction
2. `@eggjs/redis` plugin attaches the `ready` listener later in
`registerBeforeStart`
3. The `ready` event is missed, causing the app to wait forever

## Solution

Auto-enable `weakDependent` mode when `config.redis.Redis` is set to a
custom class. This skips the blocking `ready` event check, which is safe
for mock clients that are immediately ready.

## Changes

### `plugins/redis/src/lib/redis.ts`
- Detect custom Redis class and auto-enable weakDependent

### `plugins/redis/src/config/config.default.ts`
- Updated `Redis` config JSDoc with ioredis-mock usage example

### `plugins/redis/README.md`
- Added "Using ioredis-mock for Unit Tests" section with install,
configure, and notes

### Tests
- Added `redisapp-mock` fixture with ioredis-mock config
- Added 3 test cases: HTTP request, setex/get, del

## Usage

```ts
// config/config.unittest.ts
import RedisMock from 'ioredis-mock';

export default function () {
  return {
    redis: {
      Redis: RedisMock,
      client: { host: '127.0.0.1', port: 6379, password: '', db: 0 },
    },
  };
}
```

Then remove the `redis` service from your CI workflow — no real Redis
needed for unit tests.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Documentation**
* Added comprehensive Redis plugin integration guide with configuration
examples for single-client, multi-client, and cluster setups.
* Included testing guidance and examples using ioredis-mock for unit
tests with weakDependent configuration details.
* Added Chinese translations of Redis tutorials and plugin
documentation.

* **Tests**
* Added test suite for ioredis-mock support with setup and validation
tests.

* **Chores**
  * Added ioredis-mock as a development dependency.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: fengmk2

plugins/redis/README.md

@@ -277,6 +277,49 @@ Stop test redis service
 docker compose -f docker-compose.yml down
 ```
 
+## Using ioredis-mock for Unit Tests
+
+You can use [ioredis-mock](https://github.com/stipsan/ioredis-mock) to replace the real Redis client in unit tests. This eliminates the need for a running Redis server during testing, making your CI faster and local development simpler.
+
+### Install
+
+```bash
+npm i --save-dev ioredis-mock @types/ioredis-mock
+```
+
+### Configure
+
+In your test config (e.g., `config/config.unittest.ts`), override the `Redis` class:
+
+```ts
+import RedisMock from 'ioredis-mock';
+import type { EggAppInfo, PartialEggConfig } from 'egg';
+
+export default function (_appInfo: EggAppInfo): PartialEggConfig {
+  return {
+    redis: {
+      Redis: RedisMock,
+      client: {
+        host: '127.0.0.1',
+        port: 6379,
+        password: '',
+        db: 0,
+        weakDependent: true,
+      },
+    },
+  };
+}
+```
+
+> **Important**: You must set `weakDependent: true` when using `ioredis-mock`. Mock clients emit the `ready` event synchronously during construction, before the plugin's listener is attached. Without `weakDependent: true`, the app will hang on startup waiting for a `ready` event that was already emitted.
+
+### Notes
+
+- `ioredis-mock` provides an in-memory Redis implementation that supports most common commands (`get`, `set`, `setex`, `del`, `incr`, `zadd`, `zpopmin`, `zcount`, etc.)
+- Each test worker gets an isolated in-memory Redis instance
+- For production deployment testing, you should still use a real Redis server
+- You can remove `redis` service containers from your CI workflow when using `ioredis-mock` for unit tests
+
 ## Questions & Suggestions
 
 Please open an issue [here](https://github.com/eggjs/egg/issues).

plugins/redis/package.json

@@ -61,6 +61,7 @@
     "@types/node": "catalog:",
     "detect-port": "^2.1.0",
     "egg": "workspace:*",
+    "ioredis-mock": "catalog:",
     "typescript": "catalog:"
   },
   "peerDependencies": {

plugins/redis/src/config/config.default.ts

@@ -50,7 +50,28 @@ export interface RedisConfig {
    */
   agent: boolean;
   /**
-   * Customize iovalkey version, only set when you needed
+   * Customize Redis client class. Use this to replace ioredis with a compatible
+   * alternative, such as iovalkey or ioredis-mock for unit testing.
+   *
+   * When using ioredis-mock, you must also set `weakDependent: true` in the
+   * client config to avoid startup hangs (mock clients emit 'ready' synchronously
+   * before the plugin's listener is attached).
+   *
+   * @example
+   * ```ts
+   * // config/config.unittest.ts
+   * import RedisMock from 'ioredis-mock';
+   * import type { EggAppInfo, PartialEggConfig } from 'egg';
+   *
+   * export default function (_appInfo: EggAppInfo): PartialEggConfig {
+   *   return {
+   *     redis: {
+   *       Redis: RedisMock,
+   *       client: { host: '127.0.0.1', port: 6379, password: '', db: 0, weakDependent: true },
+   *     },
+   *   };
+   * }
+   * ```
    *
    * Default to `undefined`, which means using the built-in ioredis
    */

plugins/redis/test/fixtures/apps/redisapp-mock/app/controller/home.js

@@ -0,0 +1,9 @@
+module.exports = (app) => {
+  return class HomeController extends app.Controller {
+    async index() {
+      const { ctx, app } = this;
+      await app.redis.set('foo', 'bar');
+      ctx.body = await app.redis.get('foo');
+    }
+  };
+};

plugins/redis/test/fixtures/apps/redisapp-mock/app/router.js

@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = function (app) {
+  app.get('/', 'home.index');
+};

plugins/redis/test/fixtures/apps/redisapp-mock/config/config.js

@@ -0,0 +1,20 @@
+const RedisMock = require('ioredis-mock');
+
+exports.redis = {
+  Redis: RedisMock,
+  client: {
+    host: '127.0.0.1',
+    port: 6379,
+    password: '',
+    db: 0,
+    weakDependent: true,
+  },
+};
+
+exports.logger = {
+  coreLogger: {
+    level: 'INFO',
+  },
+};
+
+exports.keys = 'keys';

plugins/redis/test/fixtures/apps/redisapp-mock/config/plugin.js

@@ -0,0 +1,4 @@
+exports.redis = {
+  enable: true,
+  package: '@eggjs/redis',
+};

plugins/redis/test/fixtures/apps/redisapp-mock/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "redisapp-mock"
+}

plugins/redis/test/redis.test.ts

@@ -1,3 +1,4 @@
+import assert from 'node:assert/strict';
 import compile from 'node:child_process';
 import path from 'node:path';
 
@@ -196,3 +197,32 @@ describe.skipIf(skip)('test/redis.test.ts', () => {
     });
   });
 });
+
+describe('ioredis-mock', () => {
+  let app: MockApplication;
+  beforeAll(async () => {
+    app = mm.app({
+      baseDir: getFixtures('apps/redisapp-mock'),
+    });
+    await app.ready();
+  });
+  afterAll(() => app.close());
+  afterEach(mm.restore);
+
+  it('should work with ioredis-mock (no real Redis needed)', () => {
+    return app.httpRequest().get('/').expect(200).expect('bar');
+  });
+
+  it('should support setex and get', async () => {
+    await app.redis.setex('test-key', 60, 'test-value');
+    const val = await app.redis.get('test-key');
+    assert.equal(val, 'test-value');
+  });
+
+  it('should support del', async () => {
+    await app.redis.set('del-key', 'val');
+    await app.redis.del('del-key');
+    const val = await app.redis.get('del-key');
+    assert.equal(val, null);
+  });
+});