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/** * Mock Kuzu client for testing * CONTEXT: Database mocking for isolated unit tests * REASON: Avoid real database dependencies in unit tests * CHANGE: In-memory mock implementation with query simulation * PREVENTION: Test flakiness, database cleanup issues, external dependencies */ import { jest } from '@jest/globals'; export class MockKuzuClient { constructor(config = {}) { this.config = config; this.isConnected = false; this.nodes = new Map(); this.relationships = new Map(); this.queryHistory = []; this.transactionActive = false; // Mock data store this.mockData = { CodeEntity: new Map(), Pattern: new Map(), Rule: new Map(), Standard: new Map(), relationships: new Map() }; // Performance metrics this.metrics = { queryCount: 0, averageQueryTime: 50, connectionCount: 0 }; } async connect() { if (this.isConnected) { throw new Error('Already connected'); } this.isConnected = true; this.metrics.connectionCount++; // Simulate connection delay await new Promise(resolve => setTimeout(resolve, 10)); return true; } async close() { if (!this.isConnected) { return false; } this.isConnected = false; this.clearAllData(); return true; } async query(cypherQuery, params = {}) { if (!this.isConnected) { throw new Error('Database not connected'); } this.metrics.queryCount++; this.queryHistory.push({ query: cypherQuery, params, timestamp: Date.now() }); // Simulate query execution time await new Promise(resolve => setTimeout(resolve, Math.random() * this.metrics.averageQueryTime) ); // Parse and execute mock query return this.executeMockQuery(cypherQuery, params); } async createNode(label, properties) { if (!this.isConnected) { throw new Error('Database not connected'); } const id = properties.id || `mock-${Date.now()}-${Math.random()}`; const node = { id, label, ...properties }; if (!this.mockData[label]) { this.mockData[label] = new Map(); } this.mockData[label].set(id, node); this.nodes.set(id, node); return node; } async createRelationship(fromId, relationshipType, toId, properties = {}) { if (!this.isConnected) { throw new Error('Database not connected'); } const fromNode = this.nodes.get(fromId); const toNode = this.nodes.get(toId); if (!fromNode || !toNode) { throw new Error('One or both nodes not found'); } const relId = `rel-${Date.now()}-${Math.random()}`; const relationship = { id: relId, type: relationshipType, from: fromId, to: toId, ...properties }; this.relationships.set(relId, relationship); if (!this.mockData.relationships.has(relationshipType)) { this.mockData.relationships.set(relationshipType, []); } this.mockData.relationships.get(relationshipType).push(relationship); return relationship; } executeMockQuery(cypherQuery, params) { const query = cypherQuery.toLowerCase().trim(); // Match CREATE operations if (query.includes('create node table')) { return [{ success: true, message: 'Table created' }]; } if (query.includes('create rel table')) { return [{ success: true, message: 'Relationship table created' }]; } // Match MATCH operations if (query.includes('match')) { return this.executeMockMatch(cypherQuery, params); } // Match CREATE operations if (query.includes('create (')) { return this.executeMockCreate(cypherQuery, params); } // Match COUNT operations if (query.includes('count(')) { return this.executeMockCount(cypherQuery, params); } // Match RETURN operations if (query.includes('return')) { return this.executeMockReturn(cypherQuery, params); } // Default response return [{ result: 'success', affectedRows: 1 }]; } executeMockMatch(cypherQuery, params) { const results = []; // Extract node labels from query const labelMatches = cypherQuery.match(/\((\w+):(\w+)\)/g); if (labelMatches) { for (const match of labelMatches) { const [, variable, label] = match.match(/\((\w+):(\w+)\)/); if (this.mockData[label]) { for (const [id, node] of this.mockData[label]) { const result = {}; result[variable] = node; results.push(result); } } } } // Apply WHERE conditions if present if (cypherQuery.includes('WHERE')) { return this.applyWhereClause(results, cypherQuery, params); } return results; } executeMockCreate(cypherQuery, params) { // Extract label and properties from CREATE query const createMatch = cypherQuery.match(/CREATE \((\w+):(\w+)\s*\{([^}]+)\}\)/); if (createMatch) { const [, variable, label, propsString] = createMatch; // Parse properties const properties = this.parseProperties(propsString, params); const node = this.createNode(label, properties); const result = {}; result[variable] = node; return [result]; } return [{ created: true }]; } executeMockCount(cypherQuery, params) { const countMatch = cypherQuery.match(/count\((\w+)\)/); if (countMatch) { const [, variable] = countMatch; // Find the label from the MATCH clause const labelMatch = cypherQuery.match(new RegExp(`\\(${variable}:(\\w+)\\)`)); if (labelMatch) { const [, label] = labelMatch; const count = this.mockData[label] ? this.mockData[label].size : 0; return [{ [`count(${variable})`]: count }]; } } return [{ count: 0 }]; } executeMockReturn(cypherQuery, params) { // Simple return statement handling if (cypherQuery.includes('RETURN 1')) { return [{ '1': 1 }]; } return [{ result: 'returned' }]; } applyWhereClause(results, cypherQuery, params) { const whereClause = cypherQuery.match(/WHERE\s+(.+?)(?:\s+RETURN|\s+WITH|$)/i); if (!whereClause) { return results; } const condition = whereClause[1].trim(); return results.filter(result => { // Simple property matching if (condition.includes('=')) { const [left, right] = condition.split('=').map(s => s.trim()); // Handle parameter substitution let rightValue = right; if (right.startsWith('$')) { const paramName = right.substring(1); rightValue = params[paramName]; } else if (right.startsWith("'") && right.endsWith("'")) { rightValue = right.slice(1, -1); } // Extract property value from result const leftParts = left.split('.'); if (leftParts.length === 2) { const [variable, property] = leftParts; const node = result[variable]; if (node && node[property] === rightValue) { return true; } } } return false; }); } parseProperties(propsString, params) { const properties = {}; const propPairs = propsString.split(','); for (const pair of propPairs) { const [key, value] = pair.split(':').map(s => s.trim()); if (value.startsWith('$')) { const paramName = value.substring(1); properties[key] = params[paramName]; } else if (value.startsWith("'") && value.endsWith("'")) { properties[key] = value.slice(1, -1); } else { properties[key] = value; } } return properties; } // Test utilities clearAllData() { this.nodes.clear(); this.relationships.clear(); for (const store of Object.values(this.mockData)) { if (store instanceof Map) { store.clear(); } } this.queryHistory = []; } getQueryHistory() { return [...this.queryHistory]; } getMetrics() { return { ...this.metrics }; } setMockData(label, data) { if (!this.mockData[label]) { this.mockData[label] = new Map(); } if (Array.isArray(data)) { data.forEach(item => { const id = item.id || `mock-${Date.now()}-${Math.random()}`; this.mockData[label].set(id, { id, ...item }); this.nodes.set(id, { id, label, ...item }); }); } else { const id = data.id || `mock-${Date.now()}-${Math.random()}`; this.mockData[label].set(id, { id, ...data }); this.nodes.set(id, { id, label, ...data }); } } getMockData(label) { return this.mockData[label] ? Array.from(this.mockData[label].values()) : []; } // Simulate database errors simulateError(errorType = 'connection') { const errors = { connection: () => { throw new Error('Connection lost'); }, query: () => { throw new Error('Query execution failed'); }, timeout: () => { throw new Error('Query timeout'); }, constraint: () => { throw new Error('Constraint violation'); } }; if (errors[errorType]) { errors[errorType](); } } // Simulate performance issues setQueryDelay(delayMs) { this.metrics.averageQueryTime = delayMs; } // Transaction simulation async beginTransaction() { this.transactionActive = true; return { success: true }; } async commitTransaction() { this.transactionActive = false; return { success: true }; } async rollbackTransaction() { this.transactionActive = false; // In a real scenario, this would undo changes return { success: true }; } } // Factory function for tests export function createMockKuzuClient(config = {}) { return new MockKuzuClient(config); } // Jest mock factory export const mockKuzuClientFactory = jest.fn(() => new MockKuzuClient());