Special Customer Withdraw

[dwildt]

As a Special Customer
I can request more money than my Account Balance
In order to use my extra balance

Given that I have a 300 reais balance 
    AND an extra limit of 200 reais 
When I withdraw 301 reais
Then my balance should be -1 reais 

Given that I have a 300 reais balance 
    AND an extra limit of 200 reais 
When I withdraw 500 reais
Then my balance should be -200 reais 
	 
Given that I have a 300 reais balance 
    AND an extra limit of 200 reais 
When I withdraw 501 reais
Then a message shows saying "Can't withdraw more than account limit"