You might want to use (binary) files in your Multistep checks. For example, you might want to upload a file to an API endpoint using a binary body. Or, you might want to validate some aspect of a file that is available for download on your app.

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Testing uploads using HTTP POST requests

To test any binary uploads, you need to provide a file object. Currently, Checkly does not have a dedicated storage layer where you could upload that file, so you need to host it yourself at a (publicly) accessible location like an AWS S3 bucket, Dropbox or any other file hosting service. Having done that, you can “upload” files using a simple HTTP POST request with a (binary) body using Playwright’s built-in request object.
http-upload.spec.ts
import { test, expect } from '@playwright/test'

test('Upload a file using a POST request', async ({ request }) => {
  const fileBuffer = await test.step('Fetch file', async () => {
    const fileUrl  = 'https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf'
    return request.get(fileUrl)
  })

  await test.step('Upload file', async () => {
    const response = await request.post('https://filebin.net/pp9on3zvwv7zq6lm/dummy.pdf', {
      data: await fileBuffer.body(),
    })
    await expect(response).toBeOK()
  })
})

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Using the file system

Sometimes, you do want to explicitly save a file to disk. This is what you need to know. Checkly creates a sandboxed directory for each check run. During the run you can use this directory to save or upload artifacts. This directory is destroyed after a check is finished. 
import path from 'path'
import fs from 'fs'
import { test } from '@playwright/test'

test('Save file in directory', async ({ page }) => {
  const image = await page.goto('https://picsum.photos/200/300')
  const imagePath = path.join('example.jpg')
  const buffer = await image.body()
  fs.writeFileSync(imagePath, buffer)
  const readFileFromDisk = fs.readFileSync(imagePath)
})
Due to this sandbox, certain Node.js variables are adapted to our platform and have values we set for them. The behaviour is slightly different when creating a browser check in the Web UI or using the Checkly CLI. When creating a browser check in the Web UI, the variables are:
  • __dirname will have the value of /
  • __filename will have the value of /script.js
When creating a browser check using the Checkly CLI the variables are:
  • __dirname will have the value of /
  • __filename will have the value of the actual file in your code base, relative to the project root.