added api unit test. (fixes #2908)
added api unit test. (fixes #2908)

ShinichiU/OpenPNE3,kashiwasan/symfony-advanced,upsilon/travis-test,ShinichiU/OpenPNE3,ShinichiU/OpenPNE3,isaosano/OpenPNE3,C-nakajima/OpenPNE3,isaosano/OpenPNE3,C-nakajima/OpenPNE3,nishizoe/OpenPNE3,C-nakajima/OpenPNE3,isaosano/OpenPNE3,upsilon/travis-test,ShinichiU/OpenPNE3,C-nakajima/OpenPNE3,kashiwasan/symfony-advanced,isaosano/OpenPNE3,nishizoe/OpenPNE3