Instructions

You are working on a system to simplify the login process for your organization's network. The tasks concern the authentication part. The system uses facial recognition to prove identity.

In all occurrences the eye color parameter is guaranteed to be non-null.

1. Ensure that facial features match

Implement Authenticator.AreSameFace() to check that two faces match.

Add equality routines for the FacialFeatures class.

2. Authenticate the system administrator

Despite your protests the system administrator insists on having a built-in identity during acceptance testing so that they can always be authenticated.

The admin's email is admin@exerc.ism. They have green eyes and a philtrum with a width of 0.9.

Add equality routines for the Identity class.

Implement the Authenticator.IsAdmin() method to check that the identity passed in matches that of the administrator.

3. Register new identities

Implement the Authenticator.Register() method which stores an identity on the authenticator itself such that calls to IsRegistered() will return true for this identity: otherwise IsRegistered() returns false.

To detect duplicated attempts to register an identity, if the identity has already been registered then false is returned by Authenticator.Register(), otherwise true.

4. Prevent invalid identities being authenticated

Implement the Authenticator.IsRegistered() method and ensure it returns false when no identities have been registered.

5. Add diagnostics to detect multiple attempts to authenticate

A bug has been reported whereby the Authenticator.IsRegistered() method is called multiple times in quick succession for the same identity. You believe that there is some sort of "bounce" problem where the exact same record is being submitted multiple times. Your task is to add a diagnostic routine Authenticator.AreSameObject() to support any testing that's undertaken. The routine compares to objects and returns true if they are the exact same instance otherwise false.