Software Testing White Box

Question 1

What is White Box Testing?

Answer 1

• Also refers to as structural testing.
• Concerned with the internal path & structure of the program.
• Have knowledge of the internal working of the software.
• Tester needs to have programming skills.
• Ultimate goal is to cover all possible paths of execution of the program.

Question 2

What is Path Testing?

Answer 2

Aims to develop test cases that will guarantee execution of every program statement at least once. This helps determine all the errors and bugs underlying the program along a defined program route.

Cyclomatic complexity (CC) – a software metric to measure the complexity
of the code structure.
CC <= 4 : good
CC between 5 and 7 : medium complexity
CC between 8 and 10 : high complexity
CC > 10 : extreme complexity

Question 3

What are the steps in Path Testing?

Answer 3

• Step 1 – Construct the flow graph based on the code given
• Step 2 – Determine the Cyclomatic Complexity of the function
• Step 3 – Identify independent executable paths
• Step 4 – Design the test cases
• Step 5: Identify the input test data and expected results

Question 4

What is the cyclomatic complexity equation?

Answer 4

E - n + 2
E = Number of edges (arrows shown on a flow graph)
N = Number of nodes (circles shown on a flow graph)

Question 5

Calculate the cyclomatic complexity of this:

def computeScore(score):
studentScore = “”
if (score >= 79):
studentScore = “Distinction”
elif (score >= 59):
studentScore = “Merit”
elif (score >= 39):
studentScore = “Pass”
else:
studentScore = “Fail”
return studentScore

Answer 5

E = 12, N = 10
CC = 12 - 10 + 2 = 4

Question 6

What does the cyclomatic complexity value mean?

Answer 6

Number of executable paths

Question 7

Black Box testing vs White Box testing

Answer 7

Black Box: Conducts tests based on the functional requirements of the system.
Attempts to find errors based on external behaviours such as:
o Incorrect or missing functionality
o Interface errors
o Errors in data structure used by interfaces
Does not have knowledge of the internal working of the software.

White Box: Concerned with the internal path & structure of the program.
Ultimate goal is to cover all possible paths of execution of the program.
Have knowledge of the internal working of the software.