nsIAuthInformation.ONLY_PASSWORD

Hi All,

I am writing a test case for an asyncPromptAuth() implementation with sjs files,
and I am try to simulate a scenario that the prompt shows only password field,
that is, nsIAuthInformation.ONLY_PASSWORD is set when the authInfo is passed to
asyncPromptAuth(). But I don't know how to let caller pass such authInfo.
Could anybody tell me how to make caller pass an AuthInfo with ONLY_PASSWORD set?

Thanks,
Patrick