developed files

tests/unit/test_ai_service.py

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+"""
+Unit tests for AI document generation service
+"""
+import pytest
+from unittest.mock import AsyncMock, Mock, patch
+import asyncio
+
+from src.backend.services.ai_service import AIService, ai_service
+
+
+class TestAIService:
+    """Test AI Service functionality."""
+    
+    def test_ai_service_initialization(self):
+        """Test AI service initializes correctly."""
+        service = AIService()
+        
+        # Without API keys, clients should be None
+        assert service.claude_client is None
+        assert service.openai_client is None
+    
+    @patch('src.backend.services.ai_service.settings')
+    def test_ai_service_with_claude_key(self, mock_settings):
+        """Test AI service initialization with Claude API key."""
+        mock_settings.claude_api_key = "test-claude-key"
+        mock_settings.openai_api_key = None
+        
+        with patch('src.backend.services.ai_service.anthropic.Anthropic') as mock_anthropic:
+            service = AIService()
+            
+            mock_anthropic.assert_called_once_with(api_key="test-claude-key")
+            assert service.claude_client is not None
+            assert service.openai_client is None
+    
+    @patch('src.backend.services.ai_service.settings')
+    def test_ai_service_with_openai_key(self, mock_settings):
+        """Test AI service initialization with OpenAI API key."""
+        mock_settings.claude_api_key = None
+        mock_settings.openai_api_key = "test-openai-key"
+        
+        with patch('src.backend.services.ai_service.openai.AsyncOpenAI') as mock_openai:
+            service = AIService()
+            
+            mock_openai.assert_called_once_with(api_key="test-openai-key")
+            assert service.claude_client is None
+            assert service.openai_client is not None
+    
+    @pytest.mark.asyncio
+    async def test_generate_cover_letter_template_fallback(self):
+        """Test cover letter generation with template fallback."""
+        service = AIService()
+        
+        result = await service.generate_cover_letter(
+            job_description="Python developer position requiring FastAPI skills",
+            company_name="Tech Corp",
+            role_title="Senior Python Developer",
+            user_name="John Doe"
+        )
+        
+        assert "content" in result
+        assert "model_used" in result
+        assert "prompt" in result
+        
+        assert result["model_used"] == "template"
+        assert "Tech Corp" in result["content"]
+        assert "Senior Python Developer" in result["content"]
+        assert "John Doe" in result["content"]
+        assert "Dear Hiring Manager" in result["content"]
+    
+    @pytest.mark.asyncio
+    async def test_generate_cover_letter_with_claude(self):
+        """Test cover letter generation with Claude API."""
+        service = AIService()
+        
+        # Mock Claude client
+        mock_claude = Mock()
+        mock_response = Mock()
+        mock_response.content = [Mock(text="Generated cover letter content")]
+        mock_claude.messages.create.return_value = mock_response
+        service.claude_client = mock_claude
+        
+        result = await service.generate_cover_letter(
+            job_description="Python developer position",
+            company_name="Test Company",
+            role_title="Developer",
+            user_name="Test User"
+        )
+        
+        assert result["content"] == "Generated cover letter content"
+        assert result["model_used"] == "claude-3-haiku"
+        assert "prompt" in result
+        
+        # Verify Claude API was called correctly
+        mock_claude.messages.create.assert_called_once()
+        call_args = mock_claude.messages.create.call_args
+        assert call_args[1]["model"] == "claude-3-haiku-20240307"
+        assert call_args[1]["max_tokens"] == 1000
+    
+    @pytest.mark.asyncio
+    async def test_generate_cover_letter_with_openai(self):
+        """Test cover letter generation with OpenAI API."""
+        service = AIService()
+        
+        # Mock OpenAI client
+        mock_openai = AsyncMock()
+        mock_response = Mock()
+        mock_response.choices = [Mock(message=Mock(content="OpenAI generated content"))]
+        mock_openai.chat.completions.create.return_value = mock_response
+        service.openai_client = mock_openai
+        
+        result = await service.generate_cover_letter(
+            job_description="Software engineer role",
+            company_name="OpenAI Corp",
+            role_title="Engineer",
+            user_name="AI User"
+        )
+        
+        assert result["content"] == "OpenAI generated content"
+        assert result["model_used"] == "gpt-3.5-turbo"
+        assert "prompt" in result
+        
+        # Verify OpenAI API was called correctly
+        mock_openai.chat.completions.create.assert_called_once()
+        call_args = mock_openai.chat.completions.create.call_args
+        assert call_args[1]["model"] == "gpt-3.5-turbo"
+        assert call_args[1]["max_tokens"] == 1000
+    
+    @pytest.mark.asyncio
+    async def test_generate_cover_letter_with_user_resume(self):
+        """Test cover letter generation with user resume included."""
+        service = AIService()
+        
+        result = await service.generate_cover_letter(
+            job_description="Python developer position",
+            company_name="Resume Corp",
+            role_title="Developer",
+            user_name="Resume User",
+            user_resume="John Doe\nSoftware Engineer\n5 years Python experience"
+        )
+        
+        # Should include resume information in prompt
+        assert "Resume/Background" in result["prompt"]
+        assert result["model_used"] == "template"
+    
+    @pytest.mark.asyncio
+    async def test_generate_resume_optimization_template(self):
+        """Test resume optimization with template fallback."""
+        service = AIService()
+        
+        current_resume = "John Smith\nDeveloper\n\nExperience:\n- 3 years Python\n- Web development"
+        
+        result = await service.generate_resume_optimization(
+            current_resume=current_resume,
+            job_description="Senior Python Developer requiring FastAPI",
+            role_title="Senior Python Developer"
+        )
+        
+        assert "content" in result
+        assert "model_used" in result
+        assert "prompt" in result
+        
+        assert result["model_used"] == "template"
+        assert "Senior Python Developer" in result["content"]
+        assert current_resume in result["content"]
+    
+    @pytest.mark.asyncio
+    async def test_generate_resume_optimization_with_ai_error(self):
+        """Test resume optimization when AI service fails."""
+        service = AIService()
+        
+        # Mock Claude client that raises an exception
+        mock_claude = Mock()
+        mock_claude.messages.create.side_effect = Exception("API Error")
+        service.claude_client = mock_claude
+        
+        result = await service.generate_resume_optimization(
+            current_resume="Test resume",
+            job_description="Test job",
+            role_title="Test role"
+        )
+        
+        # Should fallback to template
+        assert result["model_used"] == "template-fallback"
+        assert "Test resume" in result["content"]
+    
+    def test_template_cover_letter_generation(self):
+        """Test template cover letter generation."""
+        service = AIService()
+        
+        content = service._generate_template_cover_letter(
+            company_name="Template Corp",
+            role_title="Template Role",
+            user_name="Template User",
+            job_description="Python, JavaScript, React, SQL, AWS, Docker experience required"
+        )
+        
+        assert "Template Corp" in content
+        assert "Template Role" in content
+        assert "Template User" in content
+        assert "Dear Hiring Manager" in content
+        
+        # Should extract and include relevant skills
+        assert "Python" in content or "Javascript" in content
+    
+    def test_template_cover_letter_no_matching_skills(self):
+        """Test template cover letter when no skills match."""
+        service = AIService()
+        
+        content = service._generate_template_cover_letter(
+            company_name="No Skills Corp",
+            role_title="Mysterious Role",
+            user_name="Skill-less User",
+            job_description="Experience with proprietary technology XYZ required"
+        )
+        
+        assert "No Skills Corp" in content
+        assert "Mysterious Role" in content
+        assert "Skill-less User" in content
+        # Should not include skill text when no matches
+        assert "with expertise in" not in content
+
+
+class TestAIServiceIntegration:
+    """Test AI service integration and edge cases."""
+    
+    @pytest.mark.asyncio
+    async def test_concurrent_cover_letter_generation(self):
+        """Test concurrent cover letter generation requests."""
+        service = AIService()
+        
+        # Create multiple concurrent requests
+        tasks = [
+            service.generate_cover_letter(
+                job_description=f"Job {i} description",
+                company_name=f"Company {i}",
+                role_title=f"Role {i}",
+                user_name=f"User {i}"
+            )
+            for i in range(5)
+        ]
+        
+        results = await asyncio.gather(*tasks)
+        
+        # All should complete successfully
+        assert len(results) == 5
+        for i, result in enumerate(results):
+            assert f"Company {i}" in result["content"]
+            assert f"Role {i}" in result["content"]
+            assert result["model_used"] == "template"
+    
+    @pytest.mark.asyncio
+    async def test_cover_letter_with_empty_inputs(self):
+        """Test cover letter generation with empty inputs."""
+        service = AIService()
+        
+        result = await service.generate_cover_letter(
+            job_description="",
+            company_name="",
+            role_title="",
+            user_name=""
+        )
+        
+        # Should handle empty inputs gracefully
+        assert "content" in result
+        assert result["model_used"] == "template"
+    
+    @pytest.mark.asyncio
+    async def test_cover_letter_with_very_long_inputs(self):
+        """Test cover letter generation with very long inputs."""
+        service = AIService()
+        
+        long_description = "A" * 10000  # Very long job description
+        
+        result = await service.generate_cover_letter(
+            job_description=long_description,
+            company_name="Long Corp",
+            role_title="Long Role",
+            user_name="Long User"
+        )
+        
+        # Should handle long inputs
+        assert "content" in result
+        assert result["model_used"] == "template"
+    
+    @pytest.mark.asyncio
+    async def test_resume_optimization_with_special_characters(self):
+        """Test resume optimization with special characters."""
+        service = AIService()
+        
+        resume_with_special_chars = """
+        José González
+        Software Engineer
+        
+        Experience:
+        • 5 years of Python development
+        • Expertise in FastAPI & PostgreSQL
+        • Led team of 10+ developers
+        """
+        
+        result = await service.generate_resume_optimization(
+            current_resume=resume_with_special_chars,
+            job_description="Senior role requiring team leadership",
+            role_title="Senior Developer"
+        )
+        
+        assert "content" in result
+        assert "José González" in result["content"]
+        assert result["model_used"] == "template"
+
+
+class TestAIServiceConfiguration:
+    """Test AI service configuration and settings."""
+    
+    @patch('src.backend.services.ai_service.settings')
+    def test_ai_service_singleton(self, mock_settings):
+        """Test that ai_service is a singleton instance."""
+        # The ai_service should be the same instance
+        from src.backend.services.ai_service import ai_service as service1
+        from src.backend.services.ai_service import ai_service as service2
+        
+        assert service1 is service2
+    
+    @pytest.mark.asyncio
+    async def test_error_handling_in_ai_generation(self):
+        """Test error handling in AI generation methods."""
+        service = AIService()
+        
+        # Mock a client that raises an exception
+        service.claude_client = Mock()
+        service.claude_client.messages.create.side_effect = Exception("Network error")
+        
+        result = await service.generate_cover_letter(
+            job_description="Test job",
+            company_name="Error Corp",
+            role_title="Error Role",
+            user_name="Error User"
+        )
+        
+        # Should fallback gracefully
+        assert result["model_used"] == "template-fallback"
+        assert "Error Corp" in result["content"]
+    
+    def test_prompt_construction(self):
+        """Test that prompts are constructed correctly."""
+        service = AIService()
+        
+        # This is tested indirectly through the template generation
+        content = service._generate_template_cover_letter(
+            company_name="Prompt Corp",
+            role_title="Prompt Engineer",
+            user_name="Prompt User",
+            job_description="Looking for someone with strong prompting skills"
+        )
+        
+        assert "Prompt Corp" in content
+        assert "Prompt Engineer" in content
+        assert "Prompt User" in content
+
+
+@pytest.mark.integration
+class TestAIServiceWithRealAPIs:
+    """Integration tests for AI service with real APIs (requires API keys)."""
+    
+    @pytest.mark.skipif(
+        not hasattr(ai_service, 'claude_client') or ai_service.claude_client is None,
+        reason="Claude API key not configured"
+    )
+    @pytest.mark.asyncio
+    async def test_real_claude_api_call(self):
+        """Test actual Claude API call (only runs if API key is configured)."""
+        result = await ai_service.generate_cover_letter(
+            job_description="Python developer position with FastAPI",
+            company_name="Real API Corp",
+            role_title="Python Developer",
+            user_name="Integration Test User"
+        )
+        
+        assert result["model_used"] == "claude-3-haiku"
+        assert len(result["content"]) > 100  # Should be substantial content
+        assert "Real API Corp" in result["content"]
+    
+    @pytest.mark.skipif(
+        not hasattr(ai_service, 'openai_client') or ai_service.openai_client is None,
+        reason="OpenAI API key not configured"
+    )
+    @pytest.mark.asyncio
+    async def test_real_openai_api_call(self):
+        """Test actual OpenAI API call (only runs if API key is configured)."""
+        # Temporarily disable Claude to force OpenAI usage
+        original_claude = ai_service.claude_client
+        ai_service.claude_client = None
+        
+        try:
+            result = await ai_service.generate_cover_letter(
+                job_description="Software engineer role requiring Python",
+                company_name="OpenAI Test Corp",
+                role_title="Software Engineer",
+                user_name="OpenAI Test User"
+            )
+            
+            assert result["model_used"] == "gpt-3.5-turbo"
+            assert len(result["content"]) > 100
+            assert "OpenAI Test Corp" in result["content"]
+        finally:
+            ai_service.claude_client = original_claude