Coverage Testing

/**
 * Coverage testing command extending TestCommand
 * Wraps test execution with c8 coverage instrumentation
 */
class CovCommand extends TestCommand {
  /** Prerequire files for coverage instrument, default false */
  prerequire: boolean;
  
  /** Coverage ignore patterns, supports multiple arguments */
  x: string[];
  
  /** c8 instruments passthrough options with defaults */
  c8: string;
  
  /**
   * Default coverage exclusion patterns
   * Includes common directories and file types to exclude from coverage
   */
  get defaultExcludes(): string[];
  
  /**
   * Overridden forkNode method that wraps test execution with c8
   * Sets up coverage instrumentation and output directories
   * @param modulePath - Path to the test runner module
   * @param args - Arguments to pass to the test runner
   */
  protected forkNode(modulePath: string, args: string[]): Promise<void>;
}

/**
 * Default coverage exclusion patterns
 * Excludes common non-production code patterns
 */
interface DefaultExclusions {
  defaultExcludes: [
    'example/',
    'examples/',  
    'mocks**/',
    'docs/',
    'test/**',
    'test{,-*}.js',
    '**/*.test.js',
    '**/__tests__/**',
    '**/node_modules/**',
    'typings',
    '**/*.d.ts'
  ];
}

/**
 * C8 coverage tool configuration
 * Provides comprehensive coverage analysis with multiple output formats
 */
interface C8Configuration {
  /** Default c8 options */
  defaultC8Options: string;  // '--temp-directory node_modules/.c8_output -r text-summary -r json-summary -r json -r lcov -r cobertura'
  
  /** Additional c8 arguments array */
  c8Args: string[];
  
  /** C8 binary path */
  c8File: string;  // 'c8/bin/c8.js'
  
  /** Temporary output directory */
  outputDir: string;  // 'node_modules/.c8_output'
  
  /** Final coverage directory */
  coverageDir: string;  // 'coverage'
}

# Basic coverage
egg-bin cov

# With custom exclusions
egg-bin cov -x "app/plugins/c*" -x "app/autocreate/**"

# With prerequire for slow-loading modules
egg-bin cov --prerequire

# Custom c8 options
egg-bin cov --c8="-r teamcity -r text"

# TypeScript coverage
egg-bin cov --typescript

/**
 * Coverage report formats and outputs
 * Generates multiple report types for different use cases
 */
interface CoverageReports {
  /** Text summary for console output */
  textSummary: boolean;
  
  /** JSON summary for programmatic access */
  jsonSummary: boolean;
  
  /** Detailed JSON report */
  json: boolean;
  
  /** LCOV format for CI/CD integration */
  lcov: boolean;
  
  /** Cobertura XML for Jenkins/Azure DevOps */
  cobertura: boolean;
  
  /** Additional formats via --c8 option */
  customFormats?: string[];  // teamcity, html, text, etc.
}

/**
 * TypeScript-specific coverage configuration
 * Handles TypeScript file extensions and compilation
 */
interface TypeScriptCoverage {
  /** TypeScript file extension support */
  extensions: string[];  // ['.ts']
  
  /** Spawn wrap shim root for TypeScript modules */
  SPAWN_WRAP_SHIM_ROOT: string;
  
  /** Additional exclusions for TypeScript */
  tsExclusions: string[];  // ['**/*.d.ts', 'typings']
}

/**
 * Coverage environment configuration
 * Controls coverage behavior and instrumentation
 */
interface CoverageEnvironment {
  /** Prerequire flag for egg-mock integration */
  EGG_BIN_PREREQUIRE?: 'true';
  
  /** Additional exclusions from environment */
  COV_EXCLUDES?: string;  // Comma-separated patterns
  
  /** Spawn wrap configuration for TypeScript */
  SPAWN_WRAP_SHIM_ROOT?: string;
}

/**
 * Coverage directory management
 * Handles cleanup and preparation of output directories
 */
interface DirectoryManagement {
  /** Removes temporary c8 output directory */
  cleanupOutputDir(outputDir: string): Promise<void>;
  
  /** Removes final coverage directory */
  cleanupCoverageDir(coverageDir: string): Promise<void>;
  
  /** Directory paths */
  directories: {
    output: string;   // 'node_modules/.c8_output'
    coverage: string; // 'coverage'
  };
}

/**
 * Coverage exclusion pattern management
 * Combines default, environment, and command-line exclusions
 */
interface ExclusionPatterns {
  /** Environment variable exclusions */
  envExclusions: string[];  // From COV_EXCLUDES
  
  /** Command-line exclusions */
  cliExclusions: string[];  // From -x arguments
  
  /** Combined exclusions set */
  allExclusions: Set<string>;
  
  /** Adds exclusion pattern to c8 arguments */
  addExclusion(pattern: string): void;
}

# Set exclusions via environment
COV_EXCLUDES="app/plugins/c*,app/autocreate/**" egg-bin cov

# Multiple exclusion sources combine
COV_EXCLUDES="vendor/**" egg-bin cov -x "temp/**" -x "cache/**"

/**
 * Prerequire mode for coverage optimization
 * Useful when mm.app or mm.cluster load files slowly
 */
interface PrerequireIntegration {
  /** Prerequire environment flag */
  EGG_BIN_PREREQUIRE: 'true';
  
  /** Integration with egg-mock */
  eggMockIntegration: boolean;
  
  /** Use case scenarios */
  useCases: [
    'Slow mm.app startup',
    'Complex mm.cluster initialization', 
    'Heavy dependency loading'
  ];
}

/**
 * C8 passthrough option system
 * Allows direct control over c8 instrumentation
 */
interface C8PassthroughOptions {
  /** Custom reporter options */
  reporters: string[];  // '-r teamcity -r text'
  
  /** Output directory override */
  outputDirectory: string;  // '--output-dir custom-coverage'
  
  /** Thresholds */
  thresholds: string;  // '--lines 80 --functions 80'
  
  /** Additional c8 flags */
  additionalFlags: string[];
}

/**
 * Coverage workflow integration
 * Supports common CI/CD and development scenarios
 */
interface CoverageIntegration {
  /** CI/CD report formats */
  ciFormats: ['lcov', 'cobertura', 'json'];
  
  /** Development formats */
  devFormats: ['text-summary', 'html'];
  
  /** Coverage badge integration */
  badgeSupport: boolean;
  
  /** Threshold enforcement */
  thresholdEnforcement: boolean;
}