How can I get test information with SonarQube API?

Now I'm trying to obtain test information with SonarQube API. Concretely, I'd like to obtain information by using api/tests/list.(http://ift.tt/1SjsEnU)

My request url is: http://localhost:9000/api/tests/list?key=org.apache.httpcomponents:httpclient&testFileId=5a3ed43a-5ae6-4154-a5bb-64c6134c69af However, I got following reply:

{"paging":{"pageIndex":1,"pageSize":100,"total":0},"tests":[]}

I DID set the BROWSER permission, but still I couldn't correct reply. What should I do to solve this problem?