ai-learning-platform/backend/src/modules/ai/tests/ai-gateway.service.spec.ts

import { Test, TestingModule } from '@nestjs/testing';
import { AIGatewayService } from '../ai-gateway.service';

describe('AIGatewayService', () => {
  let service: AIGatewayService;

  beforeEach(async () => {
    // Clear env before each test
    delete process.env.OPENAI_API_KEY;
    delete process.env.SENSENOVA_API_KEY;

    const module: TestingModule = await Test.createTestingModule({
      providers: [AIGatewayService],
    }).compile();

    service = module.get<AIGatewayService>(AIGatewayService);
  });

  describe('initialization', () => {
    it('should have no providers when no API keys set', () => {
      const providers = service.getRegisteredProviders();
      expect(providers).toEqual([]);
    });
  });

  describe('fallback mock responses', () => {
    it('should greet when asked "你好"', async () => {
      const result = await service.chat('any-model', [
        { role: 'user', content: '你好' },
      ]);

      expect(result).toContain('你好！我是宇之然 AI 助手');
    });

    it('should greet in English for "hello"', async () => {
      const result = await service.chat('any-model', [
        { role: 'user', content: 'hello' },
      ]);

      expect(result).toContain('Hello! I am YuZhiRan AI assistant');
    });

    it('should provide prompt tips when asked about 提示词', async () => {
      const result = await service.chat('any-model', [
        { role: 'user', content: '如何写好提示词？' },
      ]);

      expect(result).toContain('明确角色');
      expect(result).toContain('输出格式');
    });

    it('should provide model info when asked about 大模型', async () => {
      const result = await service.chat('any-model', [
        { role: 'user', content: '有哪些大模型？' },
      ]);

      expect(result).toContain('GPT');
      expect(result).toContain('Claude');
      expect(result).toContain('DeepSeek');
    });

    it('should return generic fallback for unknown queries', async () => {
      const result = await service.chat('any-model', [
        { role: 'user', content: '今天的天气怎么样？' },
      ]);

      expect(result).toContain('模拟模式');
      expect(result).toContain('API Key');
    });
  });

  describe('model routing', () => {
    it('should route deepseek-v4-flash to its provider (but fallback to mock)', async () => {
      const result = await service.chat('deepseek-v4-flash', [
        { role: 'user', content: '你好' },
      ]);

      // Falls back to mock since no API key
      expect(result).toContain('宇之然 AI 助手');
    });

    it('should route general model to openai provider (but fallback to mock)', async () => {
      const result = await service.chat('general', [
        { role: 'user', content: '你好' },
      ]);

      expect(result).toContain('宇之然 AI 助手');
    });

    it('should handle unknown model names by falling back', async () => {
      const result = await service.chat('unknown-model-xyz', [
        { role: 'user', content: '测试' },
      ]);

      expect(result).toContain('模拟模式');
    });
  });

  describe('contextual fallback', () => {
    it('should include user message in fallback response', async () => {
      const result = await service.chat('any', [
        { role: 'user', content: '如何学习 Python 编程？' },
      ]);

      expect(result).toContain('Python');
    });

    it('should handle multi-turn conversations', async () => {
      const messages = [
        { role: 'user' as const, content: '你是谁？' },
        { role: 'assistant' as const, content: '我是 AI 助手。' },
        { role: 'user' as const, content: '提示词有什么技巧？' },
      ];

      const result = await service.chat('any', messages);

      expect(result).toContain('提示词');
    });

    it('should truncate long user messages', async () => {
      const longMsg = 'a'.repeat(200);
      const result = await service.chat('any', [
        { role: 'user', content: longMsg },
      ]);

      expect(result).toContain('...');
    });
  });
});