The TestDiscovery YAML tests really wants our mDNS hostname to be formatted according to the Matter Core Spec

[ivmarkov]

The Matter Core Spec in section 4.3.1.1. Host Name Construction is pretty explicit as to how the mDNS hostname of the host where the Matter runs has to be constructed:

"
For DNS‑SD a target host name is required, in addition to the instance name. The target host name
SHALL be constructed using one of the available link-layer addresses, such as a 48-bit device MAC
address (for Ethernet and Wi‑Fi) or a 64-bit MAC Extended Address (for Thread) expressed as a
fixed-length twelve-character (or sixteen-character) hexadecimal string, encoded as ASCII (UTF-8)
text using capital letters, e.g., B75AFB458ECD.. In the event that a device performs MAC
address randomization for privacy, then the target host name SHALL use the privacy-preserving
randomized version and the hostname SHALL be updated in the record every time the underlying
link-layer address rotates.
"

We do the above downstream in rs-matter-embassy and rs-matter-stack where our built-in mDNS responder is used, as in that guy, we have full control over the host name.

The trouble is - if Matter is used with any of the other mDNS responders (zeroconf, astro-dnssd (Mac), Avahi-over-dBus or systemd-resolved-over-dBus) - it is not clear at all if it is possible to assign a custom hostname, and if so, how.

Therefore, for now chip_tool_tests just uses a hard-coded 001122334455 hostname with the built-in mDNS responder so that TestDiscovery is passing, but we need to figure out if we can assign a custom hostname with the other mDNS responders as well.