pub fn install_diagnostic_logger()Expand description
Install the stderr diagnostic backend for this process, once.
Call it from any test that wants to read production’s log::info! output.
It is safe to call from every test in a binary and from several binaries at
once: log::set_logger may only be called once per process, so the work is
behind a Once, and a losing call is treated as success — some other
backend is already receiving the records, which is the outcome the caller
wanted.
The level is chosen in code (Info) and is deliberately not configurable
from the environment: the workspace bans environment-dependent behaviour, and
a diagnostic you have to know an env var to see is one nobody sees.