Why white-box testing examines code internals in Testing Fundamentals - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to show what white-box testing focuses on.

Testing Fundamentals

def test_function():
    # White-box testing examines [1] of the code
    pass

Drag options to blanks, or click blank then click option'

Ainternal logic

Buser interface

Cnetwork speed

Ddatabase size

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing white-box testing with testing user interface or performance.

White-box testing looks inside the code to check the internal logic and structure.

2fill in blank

medium

Complete the code to identify a white-box testing technique.

Testing Fundamentals

def test_coverage():
    # White-box testing uses [1] to check which parts of code run
    pass

Drag options to blanks, or click blank then click option'

Ablack-box methods

Bload testing

Ccode coverage

Duser surveys

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing black-box or performance testing terms instead.

Code coverage measures which lines or branches of code are executed during tests, a white-box technique.

3fill in blank

hard

Fix the error in the white-box testing description.

Testing Fundamentals

def white_box_test():
    '''White-box testing ignores [1] and focuses on outputs.'''
    pass

Drag options to blanks, or click blank then click option'

Aexternal behavior

Buser inputs

Ccode internals

Dinternal code

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing white-box with black-box testing focus.

White-box testing does not ignore internal code; it focuses on it. It does not focus only on external behavior.

4fill in blank

hard

Fill both blanks to complete the white-box testing example.

Testing Fundamentals

def test_branch_coverage():
    for condition in conditions:
        if condition [1] True:
            execute_path = [2]
        else:
            execute_path = 'other'
    return execute_path

Drag options to blanks, or click blank then click option'

A==

B!=

C'path1'

D'path2'

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' instead of '==' for condition check.

Choosing wrong path string.

Branch coverage tests both true and false paths. The condition should be checked with '==' and the path set accordingly.

5fill in blank

hard

Fill all three blanks to complete the white-box testing dictionary comprehension.

Testing Fundamentals

coverage = {func[1]: calls for func, calls in call_counts.items() if calls [2] 0 and func.startswith([3])}

Drag options to blanks, or click blank then click option'

A()

B>

C'test_'

D[]

Attempts:

3 left

💡 Hint

Common Mistakes

Using brackets instead of parentheses for function call.

Using '<' instead of '>'.

The code builds a dictionary of functions called more than zero times and whose names start with 'test_'.

Practice

1. Why does white-box testing focus on examining the internal code of a program?

easy

A. To verify the program's performance under load

B. To check the program's user interface for usability

C. To test the program without knowing its internal workings

D. To understand the program's structure and test specific code paths

Solution

1. Step 1: Understand white-box testing purpose

   White-box testing involves looking inside the code to test its logic and paths.

2. Step 2: Compare options with testing goals

   Only To understand the program's structure and test specific code paths matches the goal of testing internal code structure and paths.

3. Final Answer:

   To understand the program's structure and test specific code paths -> Option D

4. Quick Check:

   White-box tests code internals = D [OK]

Hint: White-box tests code internals, not UI or performance [OK]

Common Mistakes:

• Confusing white-box with black-box testing
• Thinking white-box tests UI or performance
• Ignoring the code structure in white-box testing

2. Which of the following is the correct syntax to write a white-box test case in Python using the unittest framework?

easy

A. class TestFunction(unittest.TestCase):
def test_case(self):
self.assertEqual(function_to_test(), expected_value)

B. def test_function():
assert function_to_test() == expected_value

C. function test_function() {
expect(function_to_test()).toBe(expected_value);
}

D.
function_to_test() == expected_value

Solution

1. Step 1: Identify Python unittest syntax

   Python unittest requires a class inheriting unittest.TestCase and methods starting with test_.

2. Step 2: Match options to unittest style

   class TestFunction(unittest.TestCase): def test_case(self): self.assertEqual(function_to_test(), expected_value) correctly defines a test class and method using self.assertEqual.

3. Final Answer:

   class TestFunction(unittest.TestCase): def test_case(self): self.assertEqual(function_to_test(), expected_value) -> Option A

4. Quick Check:

   Python unittest uses classes and assertEqual [OK]

Hint: Python unittest tests use classes and assertEqual method [OK]

Common Mistakes:

• Using plain functions without unittest class
• Confusing JavaScript or XML syntax with Python
• Missing self parameter in test methods

3. Consider this Python function and its white-box test case:

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

# Test case
assert is_even(3) == False
assert is_even(4) == True

What is the result of running this test case?

medium

A. First assertion fails, second passes

B. Both assertions fail

C. Both assertions pass, test succeeds

D. Syntax error in test case

Solution

1. Step 1: Evaluate is_even(3)

   3 % 2 is 1, so function returns False, matching assert is_even(3) == False.

2. Step 2: Evaluate is_even(4)

   4 % 2 is 0, so function returns True, matching assert is_even(4) == True.

3. Final Answer:

   Both assertions pass, test succeeds -> Option C

4. Quick Check:

   3 odd = False, 4 even = True [OK]

Hint: Check function output matches assertion values exactly [OK]

Common Mistakes:

• Assuming 3 is even
• Confusing modulus operator result
• Thinking assert causes syntax error

4. A white-box test case for a function has this code:

def calculate_discount(price):
    if price > 100:
        return price * 0.9
    else:
        return price * 0.95

# Test
assert calculate_discount(100) == 90

What is the problem with this test?

medium

A. The test expects wrong discount for price 100

B. The function has a syntax error

C. The test should use assertEqual instead of assert

D. The function does not handle negative prices

Solution

1. Step 1: Analyze function logic for price 100

   Price 100 is not greater than 100, so else branch applies: 100 * 0.95 = 95.

2. Step 2: Compare test assertion value

   Test expects 90, but function returns 95, so assertion fails.

3. Final Answer:

   The test expects wrong discount for price 100 -> Option A

4. Quick Check:

   Price 100 gets 5% discount, test expects 10% [OK]

Hint: Check boundary conditions carefully in tests [OK]

Common Mistakes:

• Assuming price 100 triggers > 100 condition
• Thinking assert is invalid in Python
• Ignoring else branch logic

5. You want to write white-box tests to cover all branches of this function:

def classify_number(x):
    if x > 0:
        if x % 2 == 0:
            return 'Positive even'
        else:
            return 'Positive odd'
    elif x < 0:
        return 'Negative'
    else:
        return 'Zero'

Which set of test inputs covers all branches?

hard

A. [2, 4, 6]

B. [1, 2, 0, -1]

C. [0, -5]

D. [-1, 0, 1]

Solution

1. Step 1: Identify branches to cover

   Branches: x > 0 with even and odd, x < 0, and x == 0.

2. Step 2: Check test inputs for coverage

   Input 1 covers positive odd, 2 covers positive even, 0 covers zero, -1 covers negative.

3. Final Answer:

   [1, 2, 0, -1] -> Option B

4. Quick Check:

   All branches tested by these inputs [OK]

Hint: Test positive even, positive odd, zero, and negative separately [OK]

Common Mistakes:

• Missing positive odd or even cases
• Not testing zero case
• Assuming fewer inputs cover all branches