feat: add transitive dependency analysis to get_package_dependencies

- Implement recursive dependency resolution with cycle detection
- Add include_transitive and max_depth parameters
- Create dependency tree visualization with complexity scoring
- Add performance impact assessment and maintenance risk analysis
- Provide comprehensive circular dependency detection and reporting

test_transitive_deps.py

@@ -0,0 +1,124 @@
+#!/usr/bin/env python3
+"""Test script for transitive dependency functionality."""
+
+import asyncio
+import sys
+import json
+from pypi_query_mcp.tools.package_query import query_package_dependencies
+
+
+async def test_direct_dependencies():
+    """Test direct dependency querying (existing functionality)."""
+    print("Testing direct dependencies for 'requests'...")
+    try:
+        result = await query_package_dependencies("requests", include_transitive=False)
+        print(f"✓ Direct dependencies found: {len(result.get('runtime_dependencies', []))}")
+        print(f"  Package: {result.get('package_name')}")
+        print(f"  Version: {result.get('version')}")
+        print(f"  Runtime deps: {result.get('runtime_dependencies', [])[:3]}...")  # Show first 3
+        return True
+    except Exception as e:
+        print(f"✗ Error testing direct dependencies: {e}")
+        return False
+
+
+async def test_transitive_dependencies():
+    """Test transitive dependency querying (new functionality)."""
+    print("\nTesting transitive dependencies for 'requests'...")
+    try:
+        result = await query_package_dependencies(
+            "requests", 
+            include_transitive=True, 
+            max_depth=3,
+            python_version="3.10"
+        )
+        
+        print(f"✓ Transitive analysis completed")
+        print(f"  Include transitive: {result.get('include_transitive')}")
+        print(f"  Package: {result.get('package_name')}")
+        print(f"  Version: {result.get('version')}")
+        
+        # Check transitive dependency structure
+        transitive = result.get('transitive_dependencies', {})
+        all_packages = transitive.get('all_packages', {})
+        print(f"  Total packages in tree: {len(all_packages)}")
+        
+        # Check summary
+        summary = result.get('dependency_summary', {})
+        print(f"  Direct runtime deps: {summary.get('direct_runtime_count', 0)}")
+        print(f"  Total transitive packages: {summary.get('total_transitive_packages', 0)}")
+        print(f"  Max depth: {summary.get('max_dependency_depth', 0)}")
+        
+        # Check analysis
+        analysis = result.get('analysis', {})
+        performance = analysis.get('performance_impact', {})
+        print(f"  Performance level: {performance.get('performance_level', 'unknown')}")
+        
+        complexity = summary.get('complexity_score', {})
+        print(f"  Complexity level: {complexity.get('level', 'unknown')}")
+        
+        # Check circular dependencies
+        circular = transitive.get('circular_dependencies', [])
+        print(f"  Circular dependencies found: {len(circular)}")
+        
+        return True
+    except Exception as e:
+        print(f"✗ Error testing transitive dependencies: {e}")
+        import traceback
+        traceback.print_exc()
+        return False
+
+
+async def test_small_package():
+    """Test with a smaller package for faster testing."""
+    print("\nTesting transitive dependencies for 'six' (smaller package)...")
+    try:
+        result = await query_package_dependencies(
+            "six", 
+            include_transitive=True, 
+            max_depth=2
+        )
+        
+        transitive = result.get('transitive_dependencies', {})
+        all_packages = transitive.get('all_packages', {})
+        print(f"✓ Analysis completed for 'six'")
+        print(f"  Total packages: {len(all_packages)}")
+        
+        summary = result.get('dependency_summary', {})
+        print(f"  Direct runtime deps: {summary.get('direct_runtime_count', 0)}")
+        
+        return True
+    except Exception as e:
+        print(f"✗ Error testing 'six': {e}")
+        return False
+
+
+async def main():
+    """Run all tests."""
+    print("Testing PyPI Query MCP Server - Transitive Dependencies")
+    print("=" * 60)
+    
+    results = []
+    
+    # Test 1: Direct dependencies (existing functionality)
+    results.append(await test_direct_dependencies())
+    
+    # Test 2: Transitive dependencies (new functionality)
+    results.append(await test_transitive_dependencies())
+    
+    # Test 3: Small package test
+    results.append(await test_small_package())
+    
+    print("\n" + "=" * 60)
+    print(f"Test Results: {sum(results)}/{len(results)} passed")
+    
+    if all(results):
+        print("✓ All tests passed! Transitive dependency functionality is working.")
+        return 0
+    else:
+        print("✗ Some tests failed. Check the implementation.")
+        return 1
+
+
+if __name__ == "__main__":
+    sys.exit(asyncio.run(main()))