electron/spec/api-content-tracing-spec.js

const { remote } = require('electron')
const chai = require('chai')
const dirtyChai = require('dirty-chai')
const fs = require('fs')
const path = require('path')

const { expect } = chai
const { app, contentTracing } = remote

chai.use(dirtyChai)

const timeout = async (milliseconds) => {
  return new Promise((resolve) => {
    setTimeout(resolve, milliseconds)
  })
}

const getPathInATempFolder = (filename) => {
  return path.join(app.getPath('temp'), filename)
}

describe('contentTracing', () => {
  beforeEach(function () {
    // FIXME: The tests are skipped on arm/arm64.
    if (process.platform === 'linux' &&
        ['arm', 'arm64'].includes(process.arch)) {
      this.skip()
    }
  })

  const record = async (options, outputFilePath, recordTimeInMilliseconds = 1e3) => {
    await app.whenReady()

    await contentTracing.startRecording(options)
    await timeout(recordTimeInMilliseconds)
    const resultFilePath = await contentTracing.stopRecording(outputFilePath)

    return resultFilePath
  }

  const outputFilePath = getPathInATempFolder('trace.json')
  beforeEach(() => {
    if (fs.existsSync(outputFilePath)) {
      fs.unlinkSync(outputFilePath)
    }
  })

  describe('startRecording', function () {
    this.timeout(5e3)

    const getFileSizeInKiloBytes = (filePath) => {
      const stats = fs.statSync(filePath)
      const fileSizeInBytes = stats.size
      const fileSizeInKiloBytes = fileSizeInBytes / 1024
      return fileSizeInKiloBytes
    }

    it('accepts an empty config', async () => {
      const config = {}
      await record(config, outputFilePath)

      expect(fs.existsSync(outputFilePath)).to.be.true()

      const fileSizeInKiloBytes = getFileSizeInKiloBytes(outputFilePath)
      expect(fileSizeInKiloBytes).to.be.above(0,
        `the trace output file is empty, check "${outputFilePath}"`)
    })

    it('accepts a trace config', async () => {
      // (alexeykuzmin): All categories are excluded on purpose,
      // so only metadata gets into the output file.
      const config = {
        excluded_categories: ['*']
      }
      await record(config, outputFilePath)

      expect(fs.existsSync(outputFilePath)).to.be.true()

      // If the `excluded_categories` param above is not respected
      // the file size will be above 50KB.
      const fileSizeInKiloBytes = getFileSizeInKiloBytes(outputFilePath)
      const expectedMaximumFileSize = 10 // Depends on a platform.

      expect(fileSizeInKiloBytes).to.be.above(0,
        `the trace output file is empty, check "${outputFilePath}"`)
      expect(fileSizeInKiloBytes).to.be.below(expectedMaximumFileSize,
        `the trace output file is suspiciously large (${fileSizeInKiloBytes}KB),
        check "${outputFilePath}"`)
    })

    it('accepts "categoryFilter" and "traceOptions" as a config', async () => {
      // (alexeykuzmin): All categories are excluded on purpose,
      // so only metadata gets into the output file.
      const config = {
        categoryFilter: '__ThisIsANonexistentCategory__',
        traceOptions: ''
      }
      await record(config, outputFilePath)

      expect(fs.existsSync(outputFilePath)).to.be.true()

      // If the `categoryFilter` param above is not respected
      // the file size will be above 50KB.
      const fileSizeInKiloBytes = getFileSizeInKiloBytes(outputFilePath)
      const expectedMaximumFileSize = 10 // Depends on a platform.

      expect(fileSizeInKiloBytes).to.be.above(0,
        `the trace output file is empty, check "${outputFilePath}"`)
      expect(fileSizeInKiloBytes).to.be.below(expectedMaximumFileSize,
        `the trace output file is suspiciously large (${fileSizeInKiloBytes}KB),
        check "${outputFilePath}"`)
    })
  })

  describe('stopRecording', function () {
    this.timeout(5e3)

    it('calls its callback with a result file path', async () => {
      const resultFilePath = await record(/* options */ {}, outputFilePath)
      expect(resultFilePath).to.be.a('string').and.be.equal(outputFilePath)
    })

    it('creates a temporary file when an empty string is passed', async function () {
      const resultFilePath = await record(/* options */ {}, /* outputFilePath */ '')
      expect(resultFilePath).to.be.a('string').that.is.not.empty()
    })
  })
})