Previously, symlinks and relative directory imports were used in test
modules. This caused a name clash when a shared code module "common.py"
was introduced for a different test. To avoid the issue, use full paths
in imports.
The kasp test cases assume that keymgr operations on the zone under test
have been completed before the test is executed. These are typically
quite fast, but the logs need to be explicitly checked for the messages,
otherwise there's a possibility of race conditions causing the
kasp/rollover tests to become unstable.
Call the wait function in all the kasp/rollover tests where it is
expected (which is generally in each test, unless we're dealing with
unsigned zones).
Many of our test cases only use a single NamedInstance from the
`servers` fixture. Introduce `nsX` helper fixtures to simplify these
tests and reduce boilterplate code further.
Specifically, the test no longer has to either define its own variable
to extract a single server from the list, or use the longer
servers["nsX"] syntax. While this may seem minor, the amount of times it
is repeated across the tests justifies the change. It also promotes
using more explicit server identification, i.e. `nsX`, rather than
generic `server`. This also improves the clarity of the tests and may be
helpful in traceback during debugging as well.
