For e2e test in Vue Storefront we use Cypress. Head to their website for great docs, best practices and tutorial on how to write e2e tests.
We don't yet have our guidelines for e2e tests, but we try to follow best practices recommended by Cypress. Follow them to make tests more reliable and easier to maintain.
To open cypress just run:
yarn test:e2e
To run all test in background:
yarn test:e2e:ci