The test suite had grown to about 20s on my machine, but it doesn't
do much taxing work so was a good candidate to parallelise. Now runs
in under 2s on my machine.
Updates #cleanup
Change-Id: I2fcc6be9ca226c74c0cb6c906778846e959492e4
Signed-off-by: Tom Proctor <tomhjp@users.noreply.github.com>