Diagnostic Quiz

Problem

Branch Test Coverage

Suppose you have the following branch

if (Condition A) {         // Decision Point 1
    // Block 1
} else if (Condition B) {    // Decision Point 2
    // Block 2
} else {
    // Block 3
}

And you have two test cases which enter the else-if block and the else block, what will be your branch test coverage?

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Ans: 75%. The formula to calculate the branch test coverage is as follows,

$$\text{Branch Coverage} = \frac{\text{Number of Executed Branches}}{\text{Total Number of Branches}} \times 100\%$$

There are 4 distinct branches (outcomes) in this problem:

1. Branch 1: Condition A is True (Enters Block 1).

2. Branch 2: Condition A is False (Proceeds to check else if).

3. Branch 3: Condition B is True (Enters Block 2).

4. Branch 4: Condition B is False (Enters Block 3/Else).

Now, let's map our specific test cases to these branches.

1. Test Case 1: Executes the else if block

   • For the code to reach the else if block, Condition A must be False. (Covers Branch 2)

   • Then, Condition B must be True. (Covers Branch 3)

2. Test Case 2: Executes the else block

   • For the code to reach the else, Condition A must be False. (Covers Branch 2 again)

   • Then, Condition B must be False. (Covers Branch 4)

So, the number of executed branches is 3, and as the total is 4, the branch test coverage will be 75%.

This question has appeared in CS2113 AY25/26 Sem 1 Final!