Branch coverage in Testing Fundamentals - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Branch Coverage Basics

Which statement best describes branch coverage in software testing?

A It checks if all functions in the program have been called at least once.

B It counts how many lines of code have been executed during testing.

C It measures whether each possible branch (true/false) of every decision point has been executed at least once.

D It verifies that all variables have been assigned values during testing.

💡 Hint

Think about decisions in code like if statements and their possible paths.

Branch coverage ensures that each decision's possible outcomes (branches) are tested, not just the lines of code.

❓ Predict Output

intermediate

Branch Coverage Test Result

Consider this Python function:

def check_number(x):
    if x > 0:
        return "Positive"
    else:
        return "Non-positive"

If a test suite calls check_number(5) only, what is the branch coverage?

A 75% - partial testing of branches

B 50% - only the 'x > 0' true branch was tested

C 0% - no branches were tested

D 100% - all branches were tested

💡 Hint

Think about which parts of the if statement run when x=5.

Only the true branch of the if was executed. The false branch was never tested.

❓ assertion

advanced

Correct Assertion for Branch Coverage

Given this test code snippet for a function is_even(n) that returns True if n is even, which assertion best checks that both branches of the function are tested?

Testing Fundamentals

def test_is_even():
    # Which assertions ensure full branch coverage?
    pass

A assert is_even(0) == True

B assert is_even(2) == True

C assert is_even(3) == False

D assert is_even(2) == True and is_even(3) == False

💡 Hint

To cover branches, test both even and odd inputs.

Testing only one input covers one branch. Testing both even and odd covers both branches.

🔧 Debug

advanced

Identify Branch Coverage Issue in Test Cases

Here is a function and its test cases:

def classify_age(age):
    if age < 13:
        return "Child"
    elif age < 20:
        return "Teen"
    else:
        return "Adult"

# Test cases
assert classify_age(10) == "Child"
assert classify_age(25) == "Adult"

What is the branch coverage status of these tests?

A The tests miss the 'Teen' branch, so branch coverage is incomplete.

B All branches are covered by the tests.

C The tests miss the 'Child' branch, so coverage is incomplete.

D The tests miss the 'Adult' branch, so coverage is incomplete.

💡 Hint

Check if all if and elif branches have been tested.

The 'Teen' branch (age between 13 and 19) is never tested, so branch coverage is not 100%.

❓ framework

expert

Measuring Branch Coverage with a Testing Framework

Using Python's unittest and coverage tools, which command correctly measures branch coverage for test_module.py?

A coverage run --branch -m unittest test_module.py

B coverage run -m unittest test_module.py

C unittest --branch test_module.py

D coverage branch run -m unittest test_module.py

💡 Hint

Check the coverage tool's option for branch coverage.

The --branch flag enables branch coverage measurement during test execution.