feat(e2e nightwatch): allow setting cli config option.

[aitboudad]

Hi,
This allow to run e2e with a custom config file vue-cli-service e2e --config nightwatch.config.js instead of using the internal Nightwatch config.

My use-cases is using e2e nightwatch with a custom integration like nightwatch-cucumber which seems not working with the default behavior.

// nightwatch.config.js
require('nightwatch-cucumber')({}) // is ignored when using the internal Nightwatch config.
module.exports = {
  ...
}

Thanks!

[ArielleA]

Hi,

Having the --config file option is great, but doesn't it cause that you eject? I have the same usecase for cucumber but would prefer not to keep the whole nightwatch config in my tree, only the cucumber snippet.

i.e. nightwatch.config.js
require('nightwatch-cucumber')({ cucumberArgs: [ '--require', 'test/e2e/step_definitions', '--require', 'test/e2e/steps', 'features', ], });

[aitboudad]

@ArielleA to keep the whole nightwatch config use:

const deepmerge = require('deepmerge');
...

const config = require('@vue/cli-plugin-e2e-nightwatch/nightwatch.config.js');
module.exports = deepmerge(config, {
  ...
});