Code coverage metrics in Software Engineering - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Code Coverage Types

Which type of code coverage measures whether each decision point (like an if statement) has been evaluated both true and false during testing?

A Branch coverage

B Statement coverage

C Function coverage

D Path coverage

💡 Hint

Think about coverage that checks all possible outcomes of decisions.

Branch coverage ensures that every possible branch (true and false) of decision points is tested. Statement coverage only checks if each line runs, function coverage checks if functions are called, and path coverage is more detailed, covering all possible paths.

📋 Factual

intermediate

Code Coverage Metric Calculation

If a program has 100 executable statements and a test suite executes 85 of them, what is the statement coverage percentage?

A 85%

B 15%

C 100%

D 75%

💡 Hint

Coverage percentage = (executed statements / total statements) * 100

Statement coverage is calculated by dividing the number of executed statements by the total statements, then multiplying by 100. Here, 85/100 * 100 = 85%.

🔍 Analysis

advanced

Interpreting Low Branch Coverage

A test suite shows 90% statement coverage but only 50% branch coverage. What does this most likely indicate about the tests?

A Tests are missing many functions and statements

B All functions are tested but some lines are not executed

C Tests cover all decision outcomes but miss some statements

D Most lines run but some decision outcomes are not tested

💡 Hint

Think about what branch coverage measures compared to statement coverage.

High statement coverage with low branch coverage means most lines run but some branches (true/false outcomes) of decisions are not tested. This can hide bugs in untested decision paths.

❓ Comparison

advanced

Comparing Path Coverage and Branch Coverage

Which statement best describes the difference between path coverage and branch coverage?

A Path coverage only tests function calls, branch coverage tests statements.

B Path coverage tests all possible sequences of branches, while branch coverage tests each branch once.

C Branch coverage tests all possible sequences of branches, while path coverage tests each branch once.

D Branch coverage measures code complexity, path coverage measures test duration.

💡 Hint

Consider how many combinations of branches each coverage type requires.

Path coverage requires testing every possible path through the code, which includes all combinations of branches. Branch coverage only requires each branch to be tested at least once, not all combinations.

❓ Reasoning

expert

Impact of 100% Statement Coverage on Software Quality

If a software project achieves 100% statement coverage but still has bugs, what is the most likely reason?

A The coverage tool is malfunctioning and reporting wrong results.

B The code has syntax errors that coverage tools cannot detect.

C Tests do not cover all possible input values and decision outcomes.

D 100% statement coverage guarantees no bugs exist.

💡 Hint

Think about what statement coverage measures and what it does not.

Statement coverage only ensures every line runs during tests but does not guarantee all logical paths or input cases are tested. Bugs can remain in untested decision outcomes or input scenarios.