single_sign_on.py

class FakeSingleSignOnRegistry:

    def __init__(self):
	    self.tokens = set()
	
    def register(self, credentials):
	    if are_valid(credentials):
		    toekn = SSOToken()
			self.tokens.add(token)
			return token
	
    def is_valid(self, token):
	    return token in self.tokens
		
    def end_session(self, token):
	    self.tokens.remove(token)
	
class MockSingleSignOnRegistry:

    def __init__(self, expected_token, token_is_valid=True):
	    self.expected_token = expected_token
		self.token_is_valid = token_is_valid
		self.is_valid_was_called = False
		
    def is_valid(self, token):
	    if not token == self.expected_token:
		    raise Exception("this mock was givnen an unexpected argument. Expected {0}\
			got {1}".format(self.expected_token, token))
			return self.token_is_valid
			
class SSOToken:
    pass
	
    def are_valid(credentials):
    #check the credentials
	return True