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name: serverless-testing-strategy description: (opencode-project - Skill) Implement comprehensive testing for Cloudflare Workers and SvelteKit applications using Vitest, Playwright, and Miniflare for unit, integration, and end-to-end testing in serverless environments. license: MIT scope: project

Serverless Testing Strategy

When to use this skill

When creating test suites for Cloudflare Workers, SvelteKit applications, and serverless architectures requiring comprehensive coverage of APIs, databases, and user workflows.

Instructions

Phase 1: Test Infrastructure Setup

1.1 Vitest Configuration for Workers

• Use @cloudflare/vitest-pool-workers for runtime-specific testing
• Configure isolatedStorage: true for test isolation
• Set up proper environment variable handling
• Implement coverage reporting with Istanbul

1.2 Testing Framework Integration

• Configure Playwright for E2E testing
• Set up Miniflare for Workers simulation
• Establish test database isolation
• Configure CI/CD pipeline integration

Phase 2: Unit Testing Implementation

2.1 Business Logic Testing

• Test utility functions and pure functions
• Mock external dependencies and APIs
• Test cryptographic operations with deterministic vectors
• Use AAA pattern (Arrange, Act, Assert)

2.2 Component Testing

• Test Svelte components in isolation
• Mock props and events
• Validate reactive behavior
• Test accessibility patterns

Phase 3: Integration Testing

3.1 API Testing

• Test API endpoints with cloudflare:test environment
• Verify request/response handling
• Test authentication and authorization
• Validate error handling and status codes

3.2 Database Testing

• Test D1 operations with isolated instances
• Verify query execution and results
• Test transaction rollback scenarios
• Validate data integrity constraints

3.3 Storage Testing

• Test KV session storage and TTL behavior
• Validate R2 presigned URL generation
• Test file upload/download operations
• Verify consistency patterns

Phase 4: End-to-End Testing

4.1 User Workflow Testing

• Test complete user journeys
• Validate critical application paths
• Test authentication flows
• Verify data persistence across sessions

4.2 Cross-Browser Testing

• Test on multiple browsers and devices
• Validate responsive design
• Test accessibility compliance
• Verify performance characteristics

Phase 5: Quality Assurance

5.1 Test Coverage

• Achieve >80% unit test coverage
• Maintain >70% integration test coverage
• Track coverage trends and gaps
• Focus on critical path coverage

5.2 Test Reliability

• Ensure zero flaky tests
• Implement proper test isolation
• Use deterministic test data
• Handle async operations correctly

Progressive Testing Strategy

Unit Testing Layer

Purpose: Test individual functions and components in isolation Tools: Vitest, @cloudflare/vitest-pool-workers Speed: <100ms per test Focus: Business logic, utility functions, pure functions

Integration Testing Layer

Purpose: Test interactions between components and services Tools: Vitest with cloudflare:test, Miniflare Speed: <1s per test Focus: API endpoints, database operations, external services

End-to-End Testing Layer

Purpose: Test complete user workflows and critical paths Tools: Playwright, real browsers Speed: <10s per test Focus: User journeys, authentication, critical features

Configuration Examples

Basic Vitest Setup

See references/vitest-config.md for comprehensive configuration examples.

Playwright Configuration

See references/playwright-config.md for browser testing setup.

Database Testing Patterns

See references/database-testing.md for D1 and integration testing.

Test Organization

Directory Structure

Copytests/
├── unit/                    # Unit tests for pure functions
│   ├── utils/              # Utility function tests
│   ├── crypto/             # Cryptographic operation tests
│   └── validation/         # Input validation tests
├── integration/             # API and database tests
│   ├── api/                # API endpoint tests
│   ├── database/           # Database operation tests
│   └── storage/            # KV/R2 storage tests
├── e2e/                    # End-to-end tests
│   ├── workflows/          # User workflow tests
│   ├── auth/               # Authentication flow tests
│   └── critical-paths/     # Critical application paths
├── fixtures/               # Test data and utilities
│   ├── data/               # Test data sets
│   ├── mocks/              # Mock implementations
│   └── helpers/            # Test helper functions
└── performance/            # Performance and load tests
    ├── benchmarks/         # Performance benchmarks
    └── load/               # Load testing scenarios

Naming Conventions

• Unit Tests: *.test.ts - Test individual functions
• Integration Tests: *.integration.test.ts - Test service interactions
• E2E Tests: *.e2e.test.ts - Test user workflows
• Fixtures: *.fixture.ts - Test data and setup

Advanced Patterns

Mock Strategies

See references/mocking-patterns.md for comprehensive mocking strategies.

Performance Testing

See references/performance-testing.md for test optimization techniques.

Security Testing

See references/security-testing.md for authentication and encryption testing.

CI/CD Integration

Pipeline Configuration

See references/cicd-pipeline.md for GitHub Actions and deployment pipelines.

Coverage Reporting

See references/coverage-config.md for code coverage setup and thresholds.

Quality Metrics

Coverage Targets

• Unit Tests: >80% line coverage, >75% branch coverage
• Integration Tests: >70% line coverage, >65% branch coverage
• Critical Paths: 100% coverage of authentication and core workflows

Performance Benchmarks

• Unit Test Suite: <30 seconds total execution
• Integration Test Suite: <2 minutes total execution
• E2E Test Suite: <10 minutes total execution

Quality Gates

• All tests must pass before deployment
• Coverage thresholds must be met
• No new flaky tests allowed
• Performance regressions detected

Best Practices

Test Design Principles

• Test behavior, not implementation details
• Keep tests independent and repeatable
• Use meaningful test names describing scenarios
• Mock external dependencies, not internals
• Implement proper cleanup between tests

Maintenance Guidelines

• Review and update tests regularly
• Remove obsolete or redundant tests
• Focus on high-risk areas
• Prioritize critical path coverage
• Document test purpose and scope

Troubleshooting

Common Issues

See references/troubleshooting.md for common test issues and solutions.

Debugging Strategies

See references/debugging.md for test debugging techniques.

Tools and Resources

Essential Dependencies

See references/dependencies.md for required testing libraries and tools.

Reference Documentation

See references/api-docs.md for comprehensive API documentation.