refa: use message encoder for mock bots

plugins/mock/src/adapter.ts

@@ -1,5 +1,5 @@
-import { Adapter, Bot, Channel, Context, Fragment, Universal, User } from 'koishi'
-import { MessageClient, MockMessenger } from './client'
+import { Adapter, Bot, Channel, Context, Universal, User } from 'koishi'
+import { MessageClient, MockMessageEncoder } from './client'
 import { Webhook } from './webhook'
 
 declare module 'koishi' {
@@ -21,6 +21,8 @@ export namespace MockBot {
 }
 
 export class MockBot<C extends Context = Context> extends Bot<C> {
+  static MessageEncoder = MockMessageEncoder
+
   constructor(ctx: C, config: MockBot.Config) {
     super(ctx, config)
     this.platform = 'mock'
@@ -51,11 +53,6 @@ export class MockBot<C extends Context = Context> extends Bot<C> {
       user: { id: this.selfId },
     }
   }
-
-  async sendMessage(channelId: string, fragment: Fragment, guildId?: string, options?: Universal.SendOptions) {
-    const messages = await new MockMessenger(options!.session['client'], options).send(fragment)
-    return messages.map(messages => messages.id)
-  }
 }
 
 export class MockAdapter<C extends Context = Context> extends Adapter<C, MockBot<C>> {

plugins/mock/src/client.ts

@@ -9,17 +9,13 @@ const RECEIVED_OTHERWISE = 'expected "%s" to be replied with %s but received "%s
 const RECEIVED_NTH_NOTHING = 'expected "%s" to be replied at index %s but received nothing'
 const RECEIVED_NTH_OTHERWISE = 'expected "%s" to be replied with %s at index %s but received "%s"'
 
-export class MockMessenger extends MessageEncoder<Context, MockBot> {
+export class MockMessageEncoder extends MessageEncoder<Context, MockBot> {
   private buffer = ''
 
-  constructor(private client: MessageClient, options?: Universal.SendOptions) {
-    super(client.bot, client.event.channel.id, client.event.guild?.id, options)
-  }
-
   async flush() {
     this.buffer = this.buffer.trim()
     if (!this.buffer) return
-    this.client.flush(this.buffer)
+    this.options.session?.['client']?.flush(this.buffer)
     this.buffer = ''
   }