Test coverage metrics in Testing Fundamentals - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to calculate the percentage of lines covered by tests.

Testing Fundamentals

coverage_percentage = (lines_covered / [1]) * 100

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

Atotal_tests

Btotal_lines

Clines_missed

Dlines_covered

Attempts:

3 left

💡 Hint

Common Mistakes

Using lines_covered as denominator

Using lines_missed instead of total lines

The total number of lines in the code is needed to calculate coverage percentage.

2fill in blank

medium

Complete the code to calculate branch coverage percentage.

Testing Fundamentals

branch_coverage = (covered_branches / [1]) * 100

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

Amissed_branches

Bcovered_branches

Ctotal_branches

Dtotal_lines

Attempts:

3 left

💡 Hint

Common Mistakes

Dividing by covered_branches

Using total_lines instead of total_branches

Branch coverage percentage is calculated by dividing covered branches by total branches.

3fill in blank

hard

Fix the error in the code that calculates statement coverage.

Testing Fundamentals

statement_coverage = ([1] / total_statements) * 100

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

Astatements_covered

Btotal_statements

Ctotal_tests

Dstatements_missed

Attempts:

3 left

💡 Hint

Common Mistakes

Using statements_missed in numerator

Using total_statements in numerator

Only the number of statements covered should be in the numerator to calculate coverage.

4fill in blank

hard

Fill both blanks to create a dictionary of coverage metrics for lines and branches.

Testing Fundamentals

coverage = {'lines': ([1] / total_lines) * 100, 'branches': ([2] / total_branches) * 100}

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

Alines_covered

Blines_missed

Cbranches_covered

Dbranches_missed

Attempts:

3 left

💡 Hint

Common Mistakes

Using missed counts instead of covered

Mixing lines and branches variables

Coverage percentages use the count of covered lines and branches in the numerator.

5fill in blank

hard

Fill all three blanks to create a summary report dictionary with coverage percentages and total tests run.

Testing Fundamentals

report = {'line_cov': ([1] / total_lines) * 100, 'branch_cov': ([2] / total_branches) * 100, 'tests_run': [3]

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

Alines_covered

Bbranches_covered

Ctotal_tests

Dtests_passed

Attempts:

3 left

💡 Hint

Common Mistakes

Using tests_passed instead of total_tests

Using missed counts for coverage

The report shows coverage percentages using covered counts and the total number of tests run.

Practice

1. What does test coverage metric measure in software testing?

easy

A. The time taken to run all tests

B. The number of bugs found during testing

C. The percentage of code or features tested compared to total code or features

D. The number of testers involved in the project

Solution

1. Step 1: Understand the purpose of test coverage

   Test coverage measures how much of the software is tested, usually as a percentage.

2. Step 2: Identify what is compared in coverage

   It compares tested code or features against the total code or features available.

3. Final Answer:

   The percentage of code or features tested compared to total code or features -> Option C

4. Quick Check:

   Test coverage = tested items / total items [OK]

Hint: Coverage shows tested parts over total parts [OK]

Common Mistakes:

• Confusing coverage with number of bugs
• Thinking coverage measures test duration
• Assuming coverage counts testers

2. Which of the following is the correct formula for calculating test coverage percentage?

easy

A. (Number of tested code lines / Total code lines) * 100

B. (Total tests / Number of testers) * 100

C. (Number of bugs found / Total tests) * 100

D. (Number of tests run / Total number of tests) * 100

Solution

1. Step 1: Identify what test coverage measures

   Test coverage measures how much code is tested, so it relates to tested code lines over total code lines.

2. Step 2: Match formula to coverage concept

   The formula is (tested code lines / total code lines) * 100 to get percentage coverage.

3. Final Answer:

   (Number of tested code lines / Total code lines) * 100 -> Option A

4. Quick Check:

   Coverage % = tested lines / total lines * 100 [OK]

Hint: Coverage = tested code lines divided by total lines [OK]

Common Mistakes:

• Using number of tests run instead of code lines
• Confusing bugs found with coverage
• Dividing by number of testers

3. Consider a software module with 200 lines of code. If 150 lines are executed during testing, what is the test coverage percentage?

medium

A. 85%

B. 75%

C. 65%

D. 70%

Solution

1. Step 1: Identify total and tested lines

   Total lines = 200, tested lines = 150.

2. Step 2: Calculate coverage percentage

   Coverage = (150 / 200) * 100 = 0.75 * 100 = 75%.

3. Final Answer:

   75% -> Option B

4. Quick Check:

   150/200 = 0.75 = 75% [OK]

Hint: Divide tested lines by total lines, multiply by 100 [OK]

Common Mistakes:

• Dividing total lines by tested lines
• Forgetting to multiply by 100
• Mixing up tested and total lines

4. A tester reports 90% test coverage, but some critical code paths are not tested. What is the likely issue?

medium

A. Coverage metric only measures quantity, not quality of tests

B. Tester calculated coverage incorrectly

C. Test coverage always guarantees all paths tested

D. The software has no untested code

Solution

1. Step 1: Understand what coverage measures

   Coverage measures how much code is tested but not which specific paths or quality of tests.

2. Step 2: Identify why critical paths might be missed

   High coverage can still miss important paths if tests do not cover all scenarios.

3. Final Answer:

   Coverage metric only measures quantity, not quality of tests -> Option A

4. Quick Check:

   Coverage % ≠ test quality [OK]

Hint: Coverage shows quantity, not test quality [OK]

Common Mistakes:

• Assuming coverage means all paths tested
• Blaming tester calculation without proof
• Ignoring untested critical paths

5. You have a project with 3 modules: Module A (100 lines, 80 tested), Module B (150 lines, 120 tested), Module C (50 lines, 40 tested). What is the overall test coverage percentage?

hard

A. 70%

B. 75%

C. 77.5%

D. 80%

Solution

1. Step 1: Calculate total lines and total tested lines

   Total lines = 100 + 150 + 50 = 300 lines. Tested lines = 80 + 120 + 40 = 240 lines.

2. Step 2: Calculate overall coverage percentage

   Coverage = (240 / 300) * 100 = 80%.

3. Step 3: Recalculate carefully

   Sum tested lines: 80 + 120 + 40 = 240. Sum total lines: 100 + 150 + 50 = 300. Coverage = (240/300)*100 = 80%.

4. Final Answer:

   80% -> Option D

5. Quick Check:

   Total tested / total lines = 240/300 = 80% [OK]

Hint: Sum tested and total lines, then divide and multiply by 100 [OK]

Common Mistakes:

• Averaging percentages instead of totals
• Adding percentages directly
• Mixing tested and total lines