Environments and test

I am currently learning to code however I am a bit confused in regards to the various environments and the test that re done in each environment. For example I understand DEV, INT, QA and PROD and what they are for. However I am confused at what test can be done is each of these environments. Per the research I did it seems that Functional Unit Testing is done in DEV, System Integration Testing is done in INT and User Acceptance Testing is done in QA. Is this accurate and are there an other test that can be done in these environments?