How to write registering account test cases?

This is a follow up question on this post

After tweak my code as suggestion on the original post, below is my full working code.

However, I have some problems and questions:

1. How to test createAccount() that can create account successfully or can throw exception ?

This is my test but createAccount() doesn't have parameters, so how to add input to it for testing ?

def test_canCreateAccount(ctrl):
    #valid email and password
    email = 'hello@gmail.com'
    password1 = 'beautiful'
    password2 = 'beautiful'
    account = ctrl.createAccount()
    assert account.email == email
    assert account.password == password1

2. Does createAccount() violate this sentence ? It doesn't have parameters that take input.

Write functions that take input and return a result. No side effects.

3. "if" statement in createAccount() is control flow ? If yes, whether it violate this sentence ? **

Don't use exceptions for control flow.

** Or I misunderstand about something ?

4. Ruthlessly shave functions down until they do one thing.

So, why createAccount() do 2 things ? It get value from user input then validate

5. I want email input will be shown again up to 3 times. After that, app raises exception. How to do that for easy testing ?

class CreateAccountFailed(Exception):
    pass

class PassNotValid(CreateAccountFailed):
    pass

class PassNotMatch(CreateAccountFailed):
    pass

class EmailNotOK(CreateAccountFailed):
    pass


class RegisterUI:

    def getEmail(self):
        return input("Please type an your email:")

    def getPassword1(self):
        return input("Please type a password:")

    def getPassword2(self):
        return input("Please confirm your password:")

    def getSecKey(self):
        return input("Please type your security keyword:")

    def printMessage(self, message):
        print(message)


class RegisterController:
    def __init__(self, view):
        self.view = view

    def displaymessage(self, message):
        self.view.printMessage(message)

    def ValidateEmail(self, email):
        email_obj = Email(email)
        return email_obj.isValidEmail() and not accounts.isDuplicate(email)

    def ValidatePassword(self, password):
        return Password.isValidPassword(password)

    def CheckPasswordMatch(self, password1, password2):
        return Password.isMatch(password1, password2)

    def makeAccount(self, email, password, seckey):
        return Account(Email(email), Password(password), seckey)

    def createAccount(self):
        email = self.view.getEmail()
        if not self.ValidateEmail(email):
            raise EmailNotOK("Duplicate or incorrect format")

        password1 = self.view.getPassword1()
        if not self.ValidatePassword(password1):
            raise PassNotValid("Password is not valid")

        password2 = self.view.getPassword2()
        if not self.CheckPasswordMatch(password1, password2):
            raise PassNotMatch("Passwords don't match")

        return self.makeAccount(email, password1, self.view.getSecKey())

    def tryCreateAccount(self):
        try:
            account = self.createAccount()
            self.displaymessage("Account was created successfully")
            return account
        except CreateAccountFailed as e:
            self.displaymessage(str(e))

class Register(Option):
    def execute(self):
        view = RegisterUI()
        controller_one = RegisterController(view)
        controller_one.tryCreateAccount()