DnsManagerTest failure on macOS

[sebb <se...@gmail.com>]

It looks like the failure is something to do with either my router or
my DNS settings.

I've found one way to allow the test to complete OK:
Change the DNS search domain to something other than the default of 'connect'.

I've tried both 'invalid' and '.local'; they both work.

It does not seem possible to drop the search domain entirely.
If the search entry is deleted, it is replaced with 'connect'.

I've not yet found why the default is 'connect', or why
/etc/resolve.conf has the line
domain connect
but it changes to (e.g.) for a different search domain
search invalid

Odd.
Sebb.