test: add Phase 4 database integration tests (partial)

- Add comprehensive test utilities for database testing
- Implement connection management tests for in-memory and file databases
- Add transaction tests including nested transactions and savepoints
- Test database lifecycle, error handling, and performance
- Include tests for WAL mode, connection pooling, and constraints

Part of Phase 4: Integration Testing

tests/integration/mcp-protocol/basic-connection.test.ts

@@ -0,0 +1,51 @@
+import { describe, it, expect } from 'vitest';
+import { N8NDocumentationMCPServer } from '../../../src/mcp/server';
+
+describe('Basic MCP Connection', () => {
+  it('should initialize MCP server', async () => {
+    const server = new N8NDocumentationMCPServer();
+    
+    // Test executeTool directly - it returns raw data
+    const result = await server.executeTool('get_database_statistics', {});
+    expect(result).toBeDefined();
+    expect(typeof result).toBe('object');
+    expect(result.totalNodes).toBeDefined();
+    expect(result.statistics).toBeDefined();
+    
+    await server.shutdown();
+  });
+  
+  it('should execute list_nodes tool', async () => {
+    const server = new N8NDocumentationMCPServer();
+    
+    const result = await server.executeTool('list_nodes', { limit: 5 });
+    expect(result).toBeDefined();
+    expect(typeof result).toBe('object');
+    expect(result.nodes).toBeDefined();
+    expect(Array.isArray(result.nodes)).toBe(true);
+    expect(result.nodes).toHaveLength(5);
+    expect(result.nodes[0]).toHaveProperty('nodeType');
+    expect(result.nodes[0]).toHaveProperty('displayName');
+    
+    await server.shutdown();
+  });
+  
+  it('should search nodes', async () => {
+    const server = new N8NDocumentationMCPServer();
+    
+    const result = await server.executeTool('search_nodes', { query: 'webhook' });
+    expect(result).toBeDefined();
+    expect(typeof result).toBe('object');
+    expect(result.results).toBeDefined();
+    expect(Array.isArray(result.results)).toBe(true);
+    expect(result.results.length).toBeGreaterThan(0);
+    expect(result.totalCount).toBeGreaterThan(0);
+    
+    // Should find webhook node
+    const webhookNode = result.results.find((n: any) => n.nodeType === 'nodes-base.webhook');
+    expect(webhookNode).toBeDefined();
+    expect(webhookNode.displayName).toContain('Webhook');
+    
+    await server.shutdown();
+  });
+});