Angular Unit Testing - user/register-user

[rachelrring]

This component now has the following tests:

• should create
• should initialise the registration form with empty fields
• should mark email field as invalid if email is invalid
• should mark the email field as valid if the email is valid
• should call authService.registerUser and navigate to login page on successful registration
• should invalidate form when passwords do not match
• should enable registration button only when form is valid