applets/batterymonitor: thoroughly test the battery list feature
Requires powerdevil!246 (merged) and powerdevil!247 (merged)
The code mainly contains:
- UPower mock implementation: To support the upower backend and provide custom information for testing.
- Private DBus daemon setup: To mock UPower DBus interface, a private DBus session has to be set up so the test can register a system bus.
- Test batteries can be listed in the widget, and their names and states are correct.
Replaces powerdevil!151 (closed)
Edited by Fushan Wen