Question 330 - CTFL-2018 discussion

The correct answer is D, as DT1 and DT4 would achieve full coverage of the full decision table when combined with the test cases that have already been generated for rules 1 and 4.Decision table testing is a black-box test technique that uses a table to show combinations of inputs and their associated outputs1. In this case, the inputs are the account type, the amount entered, and the expected result. The outputs are the actions taken by the ATM system. The decision table has eight rules, each corresponding to a possible combination of inputs and outputs. The test cases that have already been generated for rules 1 and 4 are:

TC1: Account = Checking, Amount = $600, Expected Result = Process the transaction

TC4: Account = Savings, Amount = Not entered, Expected Result = Generate an error message

The additional test cases are:

DT1: Account = Checking, Amount = Not entered, Expected Result = Generate an error message

DT2: Account = Savings, Amount = $100, Expected Result = Process the transaction

DT3: Account = Checking, Amount = $100, Expected Result = Process the transaction

DT4: Account = Savings, Amount = $600, Expected Result = Generate an error message

To achieve full coverage of the full decision table, two more test cases are needed that cover the remaining six rules. DT1 and DT4 cover these rules, as shown in the table below:

Therefore, option D is the correct answer.Options A, B, and C are incorrect, as they do not cover all the rules in the decision table.

Reference:1, Section 4.2.5