add test for getDistance
move setup of mock object to setup(), use constants with a better name
add test for getAbsoluteDirection
add constant for zero angle (direction)
add Absolute direction assert to the no Location and no Destination test
add zero distance constant
use Navigator.DIST_ZERO constant in test
use constant for zero angle (direction)
use Navigator.DIR_ZERO constant in test
use DIR_ZERO constant
add SPEED_ZERO constant
use Navigator.SPEED_ZERO in test
add test to test setting of a location