Refactor unit test.

Change-Id: I575f17af9ae9f0bd264cfcab0ee446b72d8bdfc2
Signed-off-by: Wei-Chung Wen <morisato3711@gmail.com>
Leverage coffee-coverage for generating code coverage report.

Change-Id: I638f2f61006df09113559c0aedc9bda9be80086c
Signed-off-by: Wei-Chung Wen <morisato3711@gmail.com>