add basic unit testing for appliance instances (incomplete)
add basic unit testing for appliance instances (incomplete)


Former-commit-id: bcdfa311c2bef88ce971b4b64385c1df2923d026
Former-commit-id: 1658c8b59f6a81edeb6797f396b2bc439592a1fa
Former-commit-id: 9abf20c83ac81aa5a496a0af208bca1606b14495
dssg/wikienergy,dssg/wikienergy,dssg/wikienergy,dssg/wikienergy,dssg/wikienergy