Testing Guide

This guide covers testing practices and procedures for Edge-Utils, ensuring code quality and reliability across edge platforms.

Testing Philosophy

Edge-Utils follows these testing principles:

Comprehensive Coverage: Test all code paths and edge cases
Platform Agnostic: Tests work across Cloudflare, Vercel, and Deno
Performance Focused: Tests validate performance characteristics
Integration Ready: Tests cover real-world usage scenarios

Test Structure

Directory Organization

tests/
├── setup.js              # Global test setup
├── cache.test.js         # Cache module tests
├── geo.test.js           # Geographic utilities tests
├── platform.test.js      # Platform detection tests
├── utils.test.js         # Core utilities tests
├── integration/          # Integration tests
│   ├── cloudflare.test.js
│   ├── vercel.test.js
│   └── deno.test.js
└── performance/          # Performance tests
    ├── cache-perf.test.js
    └── streaming-perf.test.js

Test Categories

Unit Tests: Test individual functions and classes
Integration Tests: Test module interactions
Performance Tests: Validate performance characteristics
Platform Tests: Test platform-specific behavior

Running Tests

Basic Commands

# Run all tests
npm test

# Run tests with coverage
npm run test:coverage

# Run tests in watch mode
npm run test:watch

# Run specific test file
npm test -- tests/cache.test.js

# Run tests matching pattern
npm test -- --testNamePattern="should handle TTL"

Test Configuration

Jest configuration in package.json:

{
  "jest": {
    "testEnvironment": "node",
    "setupFilesAfterEnv": ["<rootDir>/tests/setup.js"],
    "collectCoverageFrom": [
      "src/**/*.js",
      "!src/**/*.test.js"
    ],
    "coverageThreshold": {
      "global": {
        "branches": 80,
        "functions": 80,
        "lines": 80,
        "statements": 80
      }
    }
  }
}

Writing Unit Tests

Basic Test Structure

import { describe, it, expect, beforeEach, afterEach } from '@jest/globals';
import { CacheManager } from '../src/cache/index.js';
import { MemoryBackend } from '../src/cache/memory.js';

describe('CacheManager', () => {
  let cache;

  beforeEach(() => {
    cache = new CacheManager({
      backend: new MemoryBackend()
    });
  });

  afterEach(async () => {
    await cache.clear();
  });

  describe('set()', () => {
    it('should store a value', async () => {
      await cache.set('key', 'value');
      const result = await cache.get('key');
      expect(result).toBe('value');
    });

    it('should handle TTL', async () => {
      await cache.set('key', 'value', { ttl: 100 });
      await new Promise(resolve => setTimeout(resolve, 150));
      const result = await cache.get('key');
      expect(result).toBeNull();
    });
  });
});

Test Utilities

Common testing utilities in tests/setup.js:

// Global test setup
import { jest } from '@jest/globals';

// Mock timers
jest.useFakeTimers();

// Mock fetch for HTTP tests
global.fetch = jest.fn();

// Mock WebSocket
global.WebSocket = jest.fn();

// Mock performance APIs
global.performance = {
  now: jest.fn(() => Date.now()),
  mark: jest.fn(),
  measure: jest.fn()
};

// Custom matchers
expect.extend({
  toBeValidUUID(received) {
    const uuidRegex = /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;
    const pass = uuidRegex.test(received);
    return {
      message: () => `expected ${received} to be a valid UUID`,
      pass
    };
  }
});

Testing Strategies

Cache Testing

describe('Cache Backends', () => {
  describe('MemoryBackend', () => {
    let backend;

    beforeEach(() => {
      backend = new MemoryBackend();
    });

    it('should store and retrieve values', async () => {
      await backend.set('key', 'value');
      const result = await backend.get('key');
      expect(result).toBe('value');
    });

    it('should handle TTL expiration', async () => {
      await backend.set('key', 'value', { ttl: 100 });
      await new Promise(resolve => setTimeout(resolve, 150));
      const result = await backend.get('key');
      expect(result).toBeNull();
    });

    it('should handle concurrent access', async () => {
      const promises = Array.from({ length: 100 }, (_, i) =>
        backend.set(`key${i}`, `value${i}`)
      );
      await Promise.all(promises);

      const results = await Promise.all(
        Array.from({ length: 100 }, (_, i) => backend.get(`key${i}`))
      );

      results.forEach((result, i) => {
        expect(result).toBe(`value${i}`);
      });
    });
  });
});

GraphQL Testing

describe('GraphQLClient', () => {
  let client;
  let mockFetch;

  beforeEach(() => {
    mockFetch = jest.fn();
    global.fetch = mockFetch;

    client = new GraphQLClient({
      endpoint: 'https://api.example.com/graphql'
    });
  });

  it('should execute queries', async () => {
    mockFetch.mockResolvedValueOnce({
      ok: true,
      json: () => Promise.resolve({
        data: { user: { id: '1', name: 'John' } }
      })
    });

    const query = `
      query GetUser($id: ID!) {
        user(id: $id) {
          id
          name
        }
      }
    `;

    const result = await client.query(query, { id: '1' });

    expect(mockFetch).toHaveBeenCalledWith(
      'https://api.example.com/graphql',
      expect.objectContaining({
        method: 'POST',
        body: JSON.stringify({
          query: expect.stringContaining('GetUser'),
          variables: { id: '1' }
        })
      })
    );

    expect(result.data.user).toEqual({
      id: '1',
      name: 'John'
    });
  });

  it('should handle errors', async () => {
    mockFetch.mockResolvedValueOnce({
      ok: false,
      status: 400,
      json: () => Promise.resolve({
        errors: [{ message: 'Invalid query' }]
      })
    });

    const query = 'invalid query';

    await expect(client.query(query)).rejects.toThrow('GraphQL request failed');
  });
});

WebSocket Testing

describe('WebSocketManager', () => {
  let wsManager;
  let mockWebSocket;

  beforeEach(() => {
    mockWebSocket = {
      send: jest.fn(),
      close: jest.fn(),
      addEventListener: jest.fn(),
      removeEventListener: jest.fn(),
      readyState: 1
    };

    global.WebSocket = jest.fn(() => mockWebSocket);

    wsManager = new WebSocketManager({
      url: 'ws://example.com'
    });
  });

  it('should connect and send messages', async () => {
    mockWebSocket.addEventListener.mockImplementation((event, handler) => {
      if (event === 'open') {
        handler();
      }
    });

    await wsManager.connect();

    wsManager.send('test message');

    expect(mockWebSocket.send).toHaveBeenCalledWith('test message');
  });

  it('should handle connection errors', async () => {
    mockWebSocket.addEventListener.mockImplementation((event, handler) => {
      if (event === 'error') {
        handler({ error: 'Connection failed' });
      }
    });

    await expect(wsManager.connect()).rejects.toThrow('Connection failed');
  });
});

Integration Testing

Platform Integration Tests

// tests/integration/cloudflare.test.js
import { CacheManager } from '../../src/cache/index.js';
import { EdgeBackend } from '../../src/cache/edge.js';

describe('Cloudflare Integration', () => {
  let cache;

  beforeEach(() => {
    // Mock Cloudflare runtime
    global.caches = {
      default: {
        put: jest.fn(),
        match: jest.fn()
      }
    };

    cache = new CacheManager({
      backend: new EdgeBackend(),
      platform: 'cloudflare'
    });
  });

  it('should use Cloudflare cache API', async () => {
    global.caches.default.match.mockResolvedValue(null);
    global.caches.default.put.mockResolvedValue(undefined);

    await cache.set('key', 'value');

    expect(global.caches.default.put).toHaveBeenCalled();
  });
});

End-to-End Testing

describe('End-to-End Scenarios', () => {
  it('should handle complete request flow', async () => {
    // Mock all dependencies
    const mockCache = { get: jest.fn(), set: jest.fn() };
    const mockAuth = { verifyToken: jest.fn() };
    const mockGraphQL = { query: jest.fn() };

    // Set up mocks
    mockCache.get.mockResolvedValue(null);
    mockAuth.verifyToken.mockResolvedValue({ userId: '123' });
    mockGraphQL.query.mockResolvedValue({
      data: { user: { id: '123', name: 'John' } }
    });

    // Simulate complete request
    const request = new Request('http://example.com/api/user', {
      headers: { 'Authorization': 'Bearer token' }
    });

    // Process request through middleware stack
    const authResult = await mockAuth.verifyToken('token');
    const cacheResult = await mockCache.get('user:123');

    if (!cacheResult) {
      const data = await mockGraphQL.query('query { user(id: "123") { id name } }');
      await mockCache.set('user:123', data.data.user);
    }

    expect(authResult.userId).toBe('123');
    expect(mockGraphQL.query).toHaveBeenCalled();
    expect(mockCache.set).toHaveBeenCalledWith('user:123', { id: '123', name: 'John' });
  });
});

Performance Testing

Benchmark Tests

describe('Performance Benchmarks', () => {
  it('should handle high concurrent load', async () => {
    const cache = new CacheManager({
      backend: new MemoryBackend()
    });

    const startTime = Date.now();
    const operations = 1000;

    // Perform concurrent operations
    const promises = Array.from({ length: operations }, (_, i) =>
      cache.set(`key${i}`, `value${i}`)
    );

    await Promise.all(promises);

    const endTime = Date.now();
    const duration = endTime - startTime;

    // Should complete within reasonable time
    expect(duration).toBeLessThan(1000); // 1 second

    // Verify all operations succeeded
    const results = await Promise.all(
      Array.from({ length: operations }, (_, i) => cache.get(`key${i}`))
    );

    results.forEach((result, i) => {
      expect(result).toBe(`value${i}`);
    });
  });

  it('should maintain performance under memory pressure', async () => {
    const cache = new CacheManager({
      backend: new MemoryBackend(),
      maxMemory: 1024 * 1024 // 1MB limit
    });

    const largeData = 'x'.repeat(10000); // 10KB per item

    // Fill cache to near capacity
    for (let i = 0; i < 50; i++) {
      await cache.set(`key${i}`, largeData);
    }

    const startTime = Date.now();

    // Add more items (should trigger cleanup)
    for (let i = 50; i < 100; i++) {
      await cache.set(`key${i}`, largeData);
    }

    const endTime = Date.now();
    const duration = endTime - startTime;

    expect(duration).toBeLessThan(5000); // 5 seconds max
  });
});

Memory Leak Testing

describe('Memory Leak Tests', () => {
  it('should not leak memory in long-running operations', async () => {
    const cache = new CacheManager({
      backend: new MemoryBackend()
    });

    // Perform many operations
    for (let i = 0; i < 10000; i++) {
      await cache.set(`key${i}`, `value${i}`, { ttl: 1000 });
      if (i % 1000 === 0) {
        // Force garbage collection if available
        if (global.gc) {
          global.gc();
        }
      }
    }

    // Memory usage should remain reasonable
    const usage = process.memoryUsage();
    expect(usage.heapUsed).toBeLessThan(50 * 1024 * 1024); // 50MB
  });
});

Test Coverage

Coverage Requirements

Statements: >80%
Branches: >80%
Functions: >80%
Lines: >80%

Coverage Configuration

{
  "jest": {
    "collectCoverageFrom": [
      "src/**/*.js",
      "!src/**/*.test.js",
      "!src/**/index.js"  // Exclude barrel exports
    ],
    "coverageReporters": [
      "text",
      "lcov",
      "html"
    ],
    "coverageThreshold": {
      "global": {
        "branches": 80,
        "functions": 80,
        "lines": 80,
        "statements": 80
      }
    }
  }
}

Improving Coverage

// Test error conditions
it('should handle network errors', async () => {
  mockFetch.mockRejectedValueOnce(new Error('Network error'));

  await expect(client.query('query')).rejects.toThrow('Network error');
});

// Test edge cases
it('should handle empty responses', async () => {
  mockFetch.mockResolvedValueOnce({
    ok: true,
    json: () => Promise.resolve({ data: {} })
  });

  const result = await client.query('query {}');
  expect(result.data).toEqual({});
});

// Test boundary conditions
it('should handle maximum TTL', async () => {
  const maxTTL = 2147483647; // 2^31 - 1
  await cache.set('key', 'value', { ttl: maxTTL });

  // Should not throw
  const result = await cache.get('key');
  expect(result).toBe('value');
});

Continuous Integration

GitHub Actions

# .github/workflows/test.yml
name: Test

on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [18, 20]

    steps:
    - uses: actions/checkout@v3
    - name: Use Node.js ${{ matrix.node-version }}
      uses: actions/setup-node@v3
      with:
        node-version: ${{ matrix.node-version }}
    - run: npm install
    - run: npm test
    - run: npm run test:coverage

Platform-Specific Testing

# Test on multiple platforms
jobs:
  test-platforms:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        platform: [cloudflare, vercel, deno]

    steps:
    - uses: actions/checkout@v3
    - name: Test ${{ matrix.platform }}
      run: npm run test:${{ matrix.platform }}

Debugging Tests

Common Issues

Async test timeouts

it('should complete within timeout', async () => {
  // Increase timeout for slow operations
}, 10000);

Mock not working

// Reset mocks between tests
beforeEach(() => {
  jest.clearAllMocks();
});

Flaky tests

// Use retry logic for flaky tests
jest.retryTimes(3);

Debugging Tools

# Run tests with debug logging
DEBUG=* npm test

# Run single test with detailed output
npm test -- --verbose --testNamePattern="specific test"

# Generate coverage report
npm run test:coverage
open coverage/lcov-report/index.html

Best Practices

Test Organization

Group related tests in describe blocks
Use descriptive test names
Keep tests focused and small
Use beforeEach/afterEach for setup/cleanup

Mocking

Mock external dependencies
Use realistic mock data
Reset mocks between tests
Avoid mocking implementation details

Assertions

Use specific matchers (toBe, toEqual, toContain)
Test both positive and negative cases
Verify side effects
Check error conditions

Performance

Keep tests fast (< 100ms each)
Parallelize independent tests
Use appropriate timeouts
Monitor test execution time

This testing guide ensures Edge-Utils maintains high quality and reliability across all supported platforms and use cases.

Get Started

Core Features

Edge Computing

API Reference

Examples

Security

Contributing

​Testing Guide

​Testing Philosophy

​Test Structure

​Directory Organization

​Test Categories

​Running Tests

​Basic Commands

​Test Configuration

​Writing Unit Tests

​Basic Test Structure

​Test Utilities

​Testing Strategies

​Cache Testing

​GraphQL Testing

​WebSocket Testing

​Integration Testing

​Platform Integration Tests

​End-to-End Testing

​Performance Testing

​Benchmark Tests

​Memory Leak Testing

​Test Coverage

​Coverage Requirements

​Coverage Configuration

​Improving Coverage

​Continuous Integration

​GitHub Actions

​Platform-Specific Testing

​Debugging Tests

​Common Issues

​Debugging Tools

​Best Practices

​Test Organization

​Mocking

​Assertions

​Performance