When we want to test the connection to a Sonar Server, we need to answer three questions:
+ Is the provided url ok?
+ Does the sonar server asks for a login/password?
+ Are the login/password ok?
We currently need up to three queries to check that
+ /api/server to test the uri
+ /api/metrics to verify if anonymous access is permitted
+ /api/user_properties to check the user/password