Have job trigger on push to branches that haves a merge request

I would like to run a job to perform tests on a branch that is requesting to be merged. This post addresses two things.

1) The trigger `job.startOn.codeReviewOpened` only runs on the default branch. Is there a workaround to run the code that has the new feature?

2) The trigger `job.startOn.codeReviewOpened` runs, I assume, only when the code review is opened. Will it run on subsequent pushes to the branch or is there a workaround to do so? I would like to avoid triggering on every push to every branch in order to save on minutes.