Improve coverage

First of all, changes other than improving code coverages should have been submitted in another PR.
Second, I don't agree with the removal of methods, `sendVerificationEmail` and `sendPasswordRequestEmail`. If the options, `sendVerificationEmail` and `sendPasswordRequestEmail` are false, that means automatic sending of mail is diabled. In that case, these methods are needed to be invoked manually. So, these methods are required.