There is no reason networkd refuses that. Especially, when multiple
downstream interfaces are connected to the same network, it is natural to
assign the same subnet prefix to them.
Prompted by #22571.
If we assign our own test runner, passing arguments stops working
as unittest won't instantiate its own test runner after it parses
the arguments from sys.argv.
Consequence is that the tests will write to stderr now instead of
stdout since it doesn't seem possible to configure the stream that
unittest.main() will instantiate its test runner with so it'll
default to sys.stderr.
Add the "Isolated" parameter in the *.network file, e.g.,
[Bridge]
Isolated=true|false
When the Isolated parameter is true, traffic coming out of this port
will only be forward to other ports whose Isolated parameter is false.
When Isolated is not specified, the port uses the kernel default
setting (false).
The "Isolated" parameter was introduced in Linux 4.19.
See man bridge(8) for more details.
But even though the kernel and bridge/iproute2 recognize the "Isolated"
parameter, systemd-networkd did not have a way to set it.
The warning is correct, since we don't inherit the necessary
unittest.TestCase class, but that's on purpose, since the Utilities
class is not supposed to be instantiated on its own, but should
complement other classes' definitions which do inherit from the
unittest.TestCase class.
It currently works because `\(` and `\)` are not valid escape sequences,
so they're not treated differently. Using raw strings (or double
backslashes) is a more correct solution.
