test/lib/internal/test_runner/yaml_to_js.js

Node.js 18's node:test, as an npm package

// https://github.com/nodejs/node/blob/a1b27b25bb01aadd3fd2714e4b136db11b7eb85a/lib/internal/test_runner/yaml_parser.js
'use strict'
const {
  codes: {
    ERR_TEST_FAILURE
  }
} = require('#internal/errors')
const AssertionError = require('assert').AssertionError
const {
  ArrayPrototypeJoin,
  ArrayPrototypePush,
  Error,
  Number,
  NumberIsNaN,
  RegExpPrototypeExec,
  StringPrototypeEndsWith,
  StringPrototypeRepeat,
  StringPrototypeSlice,
  StringPrototypeStartsWith,
  StringPrototypeSubstring
} = require('#internal/per_context/primordials')

const kYamlKeyRegex = /^(\s+)?(\w+):(\s)+([>|][-+])?(.*)$/
const kStackDelimiter = '    at '

function reConstructError (parsedYaml) {
  if (!('error' in parsedYaml)) {
    return parsedYaml
  }
  const isAssertionError = parsedYaml.code === 'ERR_ASSERTION' ||
    'actual' in parsedYaml || 'expected' in parsedYaml || 'operator' in parsedYaml
  const isTestFailure = parsedYaml.code === 'ERR_TEST_FAILURE' || 'failureType' in parsedYaml
  const stack = parsedYaml.stack ? kStackDelimiter + ArrayPrototypeJoin(parsedYaml.stack, `\n${kStackDelimiter}`) : ''
  let error, cause

  if (isAssertionError) {
    cause = new AssertionError({
      message: parsedYaml.error,
      actual: parsedYaml.actual,
      expected: parsedYaml.expected,
      operator: parsedYaml.operator
    })
  } else {
    // eslint-disable-next-line no-restricted-syntax
    cause = new Error(parsedYaml.error)
    cause.code = parsedYaml.code
  }
  cause.stack = stack

  if (isTestFailure) {
    error = new ERR_TEST_FAILURE(cause, parsedYaml.failureType)
    error.stack = stack
  }

  parsedYaml.error = error ?? cause
  delete parsedYaml.stack
  delete parsedYaml.code
  delete parsedYaml.failureType
  delete parsedYaml.actual
  delete parsedYaml.expected
  delete parsedYaml.operator

  return parsedYaml
}

function getYamlValue (value) {
  if (StringPrototypeStartsWith(value, "'") && StringPrototypeEndsWith(value, "'")) {
    return StringPrototypeSlice(value, 1, -1)
  }
  if (value === 'true') {
    return true
  }
  if (value === 'false') {
    return false
  }
  if (value !== '') {
    const valueAsNumber = Number(value)
    return NumberIsNaN(valueAsNumber) ? value : valueAsNumber
  }
  return value
}

// This parses the YAML generated by the built-in TAP reporter,
// which is a subset of the full YAML spec. There are some
// YAML features that won't be parsed here. This function should not be exposed publicly.
function YAMLToJs (lines) {
  if (lines == null) {
    return undefined
  }
  const result = { __proto__: null }
  let isInYamlBlock = false
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i]
    if (isInYamlBlock && !StringPrototypeStartsWith(line, StringPrototypeRepeat(' ', isInYamlBlock.indent))) {
      result[isInYamlBlock.key] = isInYamlBlock.key === 'stack'
        ? result[isInYamlBlock.key]
        : ArrayPrototypeJoin(result[isInYamlBlock.key], '\n')
      isInYamlBlock = false
    }
    if (isInYamlBlock) {
      const blockLine = StringPrototypeSubstring(line, isInYamlBlock.indent)
      ArrayPrototypePush(result[isInYamlBlock.key], blockLine)
      continue
    }
    const match = RegExpPrototypeExec(kYamlKeyRegex, line)
    if (match !== null) {
      const { 1: leadingSpaces, 2: key, 4: block, 5: value } = match
      if (block) {
        isInYamlBlock = { key, indent: (leadingSpaces?.length ?? 0) + 2 }
        result[key] = []
      } else {
        result[key] = getYamlValue(value)
      }
    }
  }
  return reConstructError(result)
}

module.exports = {
  YAMLToJs
}