You are testing a task, found a bug. The developer says 'it's not a bug, it's a feature'. What will you do?

If a developer says that the observed behavior is not a bug, but a feature, you should:

1. Politely clarify whether there is documentation or requirements that describe this behavior as expected.
2. Suggest reviewing the specifications or technical requirements together to understand if the behavior meets the requirements.
3. If documentation is absent or unclear, propose to document this behavior as a question for discussion with the team or product manager.
4. If the behavior is indeed documented as a feature, accept it but record it in the test documentation to avoid misunderstandings in the future.

The main thing is to maintain a constructive dialogue and aim for mutual understanding, rather than insisting on your correctness without evidence.