I have recently read about the github flow. I am using gitflow as of now and I see that Github flow looks very interesting because it is not as heavy in terms of workflow as gitflow.
What I don't understand though is once a feature is finished, a pull request is created. How are these changes are tested before merged back in master (ready for production). In gitflow I have a CI/CD task once something is committed into release branch UAT environment is updated, and when testing is done and if everything is ok changes are merged into master and deployed. In Github flow where is the position of the UAT environment?