When we write E2E tests, we usually will start the backend and the frontend separately. The backend will keep running while we're writing tests. After we finish a new E2E test, let's say, 0.register.e2e.js, we will run it with the following command inside the front-end directory:

node_modules/.bin/vue-cli-service test:e2e 
  -t tests/e2e/specs/0.register.e2e.js

Or if your npm version is 5.2.0 or later, use the following code instead:

npx vue-cli-service test:e2e 
  -t tests/e2e/specs/0.register.e2e.js

Once we finish all the tests, it is a good practice to run all the tests again to make sure there is no accidental break. Use the following command:

npm run test:e2e

In both of these scenarios, we run our E2E tests in the local environment.