@Override
    final public void beforeTextChanged(CharSequence s, int start, int count, int after) {/*No-op*/}
Validates if the given input is a valid email address.

@param email        The email to validate.
@return {@code true} if the input is a valid email. {@code false} otherwise.
unit/BasicSample/app/src/main/java/com/example/android/testing/unittesting/BasicSample/EmailValidator.java