1.if the PIN is incorrect three times consecutively,it won't
allow any transaction further with the same card, until
fresh PIN  is generated

2.if PIN is correct, then check whether date of expiry(valid
thru) of the card to the system date(current date)(in mm/yy)
format//if current date is greater or equal then allow
transaction.

3.withdrawal amount should be less than or equal to the
available balance (depending upon the account)

4.For each new transaction system should prompt for PIN ?

5.Depending upon the withdrawal limit it should allow
withdrawal in a particular day per customer.

@Coldrt99 

hi here i will put one link it gives all functionality of ATM 
then u can write urself all the test cases 

http://www.math-cs.gordon.edu/courses/cs211/ATMExample/InitialFunctionalTests.html