add unit test for function FindPlugins
add unit test for function FindPlugins

Signed-off-by: ZouYu <fe87c7a761ef1939f89153b2599d7d74395f947c@cn.fujitsu.com>

michelleN/deployment-manager,adamreese/helm,helm/helm,michelleN/deployment-manager,michelleN/deployment-manager,adamreese/deployment-manager,helm/helm,bacongobbler/helm,michelleN/deployment-manager,adamreese/deployment-manager,adamreese/deployment-manager,adamreese/deployment-manager,adamreese/deployment-manager,adamreese/helm,bacongobbler/helm