Working in IT since last 10+ years, So testing and QA is part of development process.
After development we are managing special branch for testing.
We plan any product as bellow process.
DEV => SIT => PrePROD => PROD
in above branches SIT is going to manage by testing team only. and all task will be validated here if it meet all specified condition then and only then it will allowed to PreProd if it fail then it is rejected and given back to DEV team.