Method _applySharding

lib/codecept.js:233–260

* Apply sharding to test files based on shard configuration * * @param {Array } testFiles - Array of test file paths * @param {string} shardConfig - Shard configuration in format "index/total" (e.g., "1/4") * @returns {Array } - Filtered array of test files for this shard

(testFiles, shardConfig)

   * @returns {Array<string>} - Filtered array of test files for this shard
   */
  _applySharding(testFiles, shardConfig) {
    const shardMatch = shardConfig.match(/^(\d+)\/(\d+)$/)
    if (!shardMatch) {
      throw new Error('Invalid shard format. Expected format: "index/total" (e.g., "1/4")')
    }

    const shardIndex = parseInt(shardMatch[1], 10)
    const shardTotal = parseInt(shardMatch[2], 10)

    if (shardTotal < 1) {
      throw new Error('Shard total must be at least 1')
    }

    if (shardIndex < 1 || shardIndex > shardTotal) {
      throw new Error(`Shard index ${shardIndex} must be between 1 and ${shardTotal}`)
    }

    if (testFiles.length === 0) {
      return testFiles
    }

    // Calculate which tests belong to this shard
    const shardSize = Math.ceil(testFiles.length / shardTotal)
    const startIndex = (shardIndex - 1) * shardSize
    const endIndex = Math.min(startIndex + shardSize, testFiles.length)

    return testFiles.slice(startIndex, endIndex)
  }

  /**
   * Run a specific test or all loaded tests.