Add Sweetistics API posting support to bird

tests/sweetistics-client.test.ts

@@ -0,0 +1,50 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { SweetisticsClient } from '../src/lib/sweetistics-client.js';
+
+describe('SweetisticsClient', () => {
+  const originalFetch = globalThis.fetch;
+
+  beforeEach(() => {
+    vi.resetAllMocks();
+  });
+
+  afterEach(() => {
+    globalThis.fetch = originalFetch;
+  });
+
+  it('posts tweet with bearer token and reply id', async () => {
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: true,
+      status: 200,
+      json: async () => ({ success: true, tweetId: '123' }),
+    });
+    globalThis.fetch = fetchMock as unknown as typeof fetch;
+
+    const client = new SweetisticsClient({ baseUrl: 'https://api.example.com', apiKey: 'sweet-test' });
+    const result = await client.tweet('hello world', '456');
+
+    expect(result.success).toBe(true);
+    expect(result.tweetId).toBe('123');
+
+    expect(fetchMock).toHaveBeenCalledTimes(1);
+    const [url, init] = fetchMock.mock.calls[0];
+    expect(url).toBe('https://api.example.com/api/actions/tweet');
+    expect((init as RequestInit).headers).toMatchObject({ authorization: 'Bearer sweet-test' });
+    expect(JSON.parse((init as RequestInit).body as string)).toEqual({ text: 'hello world', replyToTweetId: '456' });
+  });
+
+  it('returns error when API responds with failure', async () => {
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: false,
+      status: 401,
+      json: async () => ({ success: false, error: 'Unauthorized' }),
+    });
+    globalThis.fetch = fetchMock as unknown as typeof fetch;
+
+    const client = new SweetisticsClient({ baseUrl: 'https://api.example.com', apiKey: 'sweet-test' });
+    const result = await client.tweet('test');
+
+    expect(result.success).toBe(false);
+    expect(result.error).toContain('Unauthorized');
+  });
+});