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


Former-commit-id: d9671819b9824c06d6ee7142caad40b9df7f3dcc [formerly f85ceddcd666a0baf91a187ab4c09315e80f4899] [formerly 62f52369d663a4385864882b4beb98b62f61ba87]
Former-commit-id: 790ea134dafcd8fae80c1c7f249c749fb4592c36
Former-commit-id: fd050cb4feb4f2dc1438462bf7c5cd55e48604ce
dssg/wikienergy,dssg/wikienergy,dssg/wikienergy,dssg/wikienergy,dssg/wikienergy