node-fs-extra/lib/move/__tests__/cross-device-utils.js

const fs = require('graceful-fs')
const path = require('path')

const { CROSS_DEVICE_PATH } = process.env
let runCrossDeviceTests = !!CROSS_DEVICE_PATH

if (runCrossDeviceTests) {
  // make sure we have permission on device
  try {
    fs.writeFileSync(path.join(CROSS_DEVICE_PATH, 'file'), 'hi')
  } catch {
    runCrossDeviceTests = false
    throw new Error(`Can't write to device ${CROSS_DEVICE_PATH}`)
  }
} else console.log('Skipping cross-device move tests')

module.exports = {
  differentDevice: CROSS_DEVICE_PATH,
  ifCrossDeviceEnabled: (fn) => runCrossDeviceTests ? fn : fn.skip
}