Trigger build on PR?

I searched around a lot for this, and there seems to be mixed results on if CircleCI supports this yet. I’m looking to trigger a build when a PR is opened against a branch, without loosing the functionality of running tests on other commits. Use case:

When i push a branch/commit i would like to run tests on that branch/commit. (Continuous INTEGRATION).

When i open a pull request against the default branch, i would like to build a Q/A asset or deploy it. (Continuous DELIVERY).

While i guess CircleCI doesn’t claim to support Continuous Delivery, it seems like every other major CI provider supports this, including the new Github Actions beta.

Currently what i do to accomplish this is have a staging branch that is considered “unstable” and to get QA assets, i have to push a new branch, open and merge a pull request, then manually create a new tag at that point. It’s just a lot of extra overhead for something that could all be done in one step. If this is not solved, I will probably be switching to GitHub Actions as soon as it is ready for production usage which really bums me out because CircleCI is almost what i need and i’ve been happy to pay for it’s services with the exception of this issue.