CLAUDE.md

• after making any code changes, run uv ruff check to make sure linting passes
• use uv to run any other necessary tasks such as pytest

Time

Production code in ably/ reads the current time and schedules delayed callbacks through the clock, never through time, datetime.now or asyncio.sleep:

• select_clock(options) in the constructor, from ably.util.clock
• now_ms() for the time of day
• monotonic_ms() for a duration
• timer(timeout_ms, callback) for a delayed callback

A test replaces it with TestOptions(clock=...). Converting a caller-supplied value, and arithmetic on the unix epoch, are not clock readings and stay as they are.

asyncio.wait_for in ConnectionManager.ping is the one delay that runs on the event loop's clock rather than this one; a test which waits it out sets a short real realtime_request_timeout.

Auth._timestamp signs a token request the server validates, so a client which reads a fake clock talks to a mock rather than to the sandbox.