The command method for serving end-points

func (c *Command) ServeHTTP(w http.ResponseWriter, r *http.Request) {...}

is also responsible for looking up named identities if one exists. Otherwise, it checks if a peer credential UID is available, even if no named local username is associated with it.

Following the addition of basic auth and certificate based identities, exactly what is passed to the response function

type ResponseFunc func(*Command, *http.Request, *UserState) Response

specifically, UserState, is more complicated to picture.

Add tests to cover all the identity types, to capture what we expect in each identity case.

The tests also highlight that components, such as notices, only supporting UID (and not yet names identities) cannot work with all named identity types.