add decoder UT module for API
Merge pull request #1228 from huili2/dec_ut_api_module

add decoder UT module for API
fix param initialization bug in UT
Merge pull request #1230 from lyao2/ut_fixbug

fix param initialization bug in UT
    add a judgment
remove test case because this issue had been fixed
Merge pull request #1233 from ruil2/interface_ut_1

    add a judgment