test: stabilize channel mode and discussion coverage

test/discussion-service.test.ts

@@ -5,7 +5,7 @@ import os from 'node:os';
 import path from 'node:path';
 
 import { createDiscussionService } from '../plugin/core/discussion-service.ts';
-import { buildDiscussionClosedMessage, buildDiscussionOriginCallbackMessage } from '../plugin/core/discussion-messages.ts';
+import { buildDiscussionClosedMessage, buildDiscussionIdleReminderMessage, buildDiscussionOriginCallbackMessage } from '../plugin/core/discussion-messages.ts';
 
 function makeLogger() {
   return {
@@ -246,6 +246,44 @@ test('handleCallback rejects an absolute path outside the initiator workspace',
   );
 });
 
+test('maybeSendIdleReminder sends exactly one idle reminder for an active discussion', async () => {
+  const workspace = makeWorkspace();
+
+  const fetchCalls: Array<{ url: string; body: any }> = [];
+  const originalFetch = globalThis.fetch;
+  globalThis.fetch = (async (url: string | URL | Request, init?: RequestInit) => {
+    const body = init?.body ? JSON.parse(String(init.body)) : undefined;
+    fetchCalls.push({ url: String(url), body });
+    return new Response(JSON.stringify({ id: `msg-${fetchCalls.length}` }), { status: 200 });
+  }) as typeof fetch;
+
+  try {
+    const service = createDiscussionService({
+      api: makeApi() as any,
+      workspaceRoot: workspace,
+      moderatorBotToken: 'bot-token',
+      forceNoReplyForSession: () => {},
+    });
+
+    await service.initDiscussion({
+      discussionChannelId: 'discussion-idle-1',
+      originChannelId: 'origin-idle-1',
+      initiatorAgentId: 'agent-idle',
+      initiatorSessionId: 'session-idle',
+      discussGuide: 'Only send one reminder.',
+    });
+
+    await service.maybeSendIdleReminder('discussion-idle-1');
+    await service.maybeSendIdleReminder('discussion-idle-1');
+
+    assert.equal(fetchCalls.length, 2);
+    assert.equal(fetchCalls[1]?.url, 'https://discord.com/api/v10/channels/discussion-idle-1/messages');
+    assert.equal(fetchCalls[1]?.body?.content, buildDiscussionIdleReminderMessage());
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
 test('handleCallback notifies the origin channel with the resolved summary path', async () => {
   const workspace = makeWorkspace();
   const summaryRelPath = path.join('plans', 'discussion-summary.md');