Black-box vs white-box testing in Testing Fundamentals - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Black-box Testing Focus

Which statement best describes the main focus of black-box testing?

A Testing internal code structure without knowing the program's inputs or outputs

B Testing the software by reviewing the source code line by line

C Testing software functionality based only on inputs and expected outputs without knowledge of internal code

D Testing the software performance by analyzing memory usage

💡 Hint

Think about testing without looking inside the program.

Black-box testing focuses on checking software behavior by providing inputs and verifying outputs without any knowledge of internal code.

🧠 Conceptual

intermediate

White-box Testing Characteristics

Which of the following is a key characteristic of white-box testing?

A It requires knowledge of the internal code and logic to design test cases

B It is performed only after black-box testing is complete

C It ignores the program's internal structure and focuses on output correctness

D It tests the software only through its user interface

💡 Hint

White-box testing means looking inside the program.

White-box testing involves understanding and testing the internal workings of the software, such as code paths and logic.

❓ Predict Output

advanced

Output of Black-box Test Case Result

Given a function that returns the sum of two numbers, what will be the output of this black-box test case if inputs are 3 and 5?

Testing Fundamentals

def add(a, b):
    return a + b

# Black-box test case
input1 = 3
input2 = 5
result = add(input1, input2)
print(result)

A TypeError

B 8

C 35

D None

💡 Hint

Think about what adding 3 and 5 returns.

The function adds two numbers and returns their sum. 3 + 5 equals 8.

❓ assertion

advanced

Correct Assertion for White-box Testing Coverage

Which assertion best verifies that a specific function branch was executed during white-box testing?

Testing Fundamentals

def is_even(num):
    if num % 2 == 0:
        return True
    else:
        return False

result = is_even(4)

A assert result == 4 # Incorrect output check

B assert 'if' in is_even.__code__.co_names # Checks code contains 'if' keyword

C assert result is not None # Checks function returns something

D assert result == True # Checks output correctness only

💡 Hint

White-box testing checks internal logic by verifying outputs for specific inputs.

The assertion checks that the function returns True for input 4, confirming the 'if' branch was executed.

🔧 Debug

expert

Identify the Testing Approach Causing a Bug Miss

A tester uses only black-box testing on a function that has a hidden division by zero error in an internal branch never triggered by normal inputs. What is the most likely outcome?

A The bug will be missed because black-box testing does not examine internal code paths

B The bug will be fixed automatically by black-box testing

C The bug will cause a syntax error during black-box testing

D The bug will be detected because black-box testing covers all internal branches

💡 Hint

Think about what black-box testing can and cannot see.

Black-box testing only tests visible inputs and outputs, so hidden internal errors in untested branches can be missed.