fix(duplicate): preserve options as well as accept overrides (#1234)

fixes #1207

src/index.js

@@ -173,8 +173,8 @@ class RedisMock extends EventEmitter {
     return pipeline.exec(callback)
   }
 
-  duplicate() {
-    const mock = new RedisMock()
+  duplicate(override) {
+    const mock = new RedisMock({ ...this.options, ...override });
     mock.expires = this.expires
     mock.data = this.data
     mock.channels = this.channels

test/integration/commands/duplicate.js

@@ -0,0 +1,15 @@
+import Redis from 'ioredis'
+
+describe('duplicate', () => {
+  it('prerequisites', () => {
+    expect(new Redis().options.lazyConnect).toBe(false)
+  })
+  it('should preserve options', () => {
+    const redis = new Redis({ lazyConnect: true })
+    expect(redis.duplicate().options.lazyConnect).toBe(true)
+  })
+  it('should handle overrides', () => {
+    const redis = new Redis({ lazyConnect: true })
+    expect(redis.duplicate({ lazyConnect: false }).options.lazyConnect).toBe(false)
+  })
+})