Support common test settings/customizations for all tests

[eastenluis]

Is your feature request related to a problem? Please describe. I cannot set a common test configs applied across test files. Since every test file is run in parallel, I have to include the config for each the test.

Describe the solution you'd like Option to pass a configuration file for specifying customization. It can be directly calling jest/puppeteer related libraries or exposing restricted APIs to be called.

Describe alternatives you've considered We may add some important configs as cli flags. But it makes the client layer too thick.

Additional context N/A

[noahnu]

Are we still interested in this? What sort of configuration are we looking for?