The true test is can it write tests? Ask the dev if they use it to write tests. The answers to #1 is it can't really. The answer to #2 should be no.
AI can write some tests, but it can't design thorough ones. Perhaps the best way to use AI is to have a human writing thorough and well documented tests as part of TDD, asking AI to write code to meet those tests, then thoroughly reviewing that code.
AI saves me just a little time by writing boilerplate stuff for me, just one step above how IDEs have been providing generated getters and setters.
AI can write some tests, but it can't design thorough ones. Perhaps the best way to use AI is to have a human writing thorough and well documented tests as part of TDD, asking AI to write code to meet those tests, then thoroughly reviewing that code.
AI saves me just a little time by writing boilerplate stuff for me, just one step above how IDEs have been providing generated getters and setters.