Add test with mock.
Add test with mock.

 * api.task()
 * api.create_task()
 * api.delete_task()
 * api.create_note()
 * api.delete_category()

Signed-off-by: Kouhei Maeda <c9f1823971fa1a4c79cdb50b3311094021cee31e@palmtb.net>

gvkalra/python-anydo,gvkalra/python-anydo