snapshots.user.js

// ==UserScript==
// @name         Hide Snapshots
// @namespace    https://github.com/ryanml
// @version      1.0
// @description  Hides testing snapshots in Github PR file view
// @author       ryanml
// @match        *://github.com/brave/brave-ui/pull/*/files
// @grant        none
// ==/UserScript==

// This can be changed
const snapshotDir = '__snapshots__'

const hideSnapshotFiles = () => {
  const files = document.querySelectorAll('.file')

  for (let f = 0; f < files.length; f++) {
    const fileLink = files[f].querySelector('.link-gray-dark')
    if (fileLink.innerHTML.indexOf(snapshotDir) > -1) {
      files[f].className = files[f].className.replace('Details--on', '')
    }
  }
}

const assemble = () => {
  const filesParent = document.querySelector('#files')
  new MutationObserver(hideSnapshotFiles)
    .observe(filesParent, {childList: true, subtree: true})
  hideSnapshotFiles()
}

window.onload = assemble