Test estimation techniques in Testing Fundamentals - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Test Estimation Methods

Which of the following best describes the Wideband Delphi test estimation technique?

A A technique that uses historical defect data to predict the number of tests needed.

B An automated tool that calculates test effort based on code complexity metrics.

C A method where a single tester estimates the time required for all test cases without consulting others.

D A group-based estimation where experts discuss and revise estimates anonymously until consensus is reached.

💡 Hint

Think about group discussions and anonymous feedback in estimation.

Wideband Delphi involves multiple experts providing estimates anonymously, discussing differences, and revising until they agree.

🧠 Conceptual

intermediate

Test Estimation Inputs

Which input is least important when preparing a test effort estimate?

A Availability and skill level of the testing team.

B Requirements complexity and clarity.

C The color scheme of the application UI.

D Historical data from similar past projects.

💡 Hint

Consider what affects test effort realistically.

The UI color scheme does not impact the effort needed to test functionality or performance.

❓ Predict Output

advanced

Output of Test Case Estimation Calculation

Given the following Python code that calculates total test effort based on test cases and average time per test, what is the output?

Testing Fundamentals

test_cases = [5, 8, 3, 10]
avg_time_per_test = 1.5  # hours

total_effort = sum(test_cases) * avg_time_per_test
print(f'Total test effort: {total_effort} hours')

A Total test effort: 39.0 hours

B Total test effort: 26.0 hours

C Total test effort: 39 hours

D Total test effort: 26 hours

💡 Hint

Sum the test cases and multiply by average time.

Sum of test_cases is 5+8+3+10=26. Multiply by 1.5 gives 39.0 hours.

❓ assertion

advanced

Valid Assertion for Test Effort Estimation

Which assertion correctly verifies that the calculated test effort is within an expected range?

Testing Fundamentals

calculated_effort = 40
expected_min = 35
expected_max = 45

A assert calculated_effort == expected_min and calculated_effort == expected_max

B assert expected_min <= calculated_effort <= expected_max

C assert calculated_effort < expected_min or calculated_effort > expected_max

D assert calculated_effort != expected_min or calculated_effort != expected_max

💡 Hint

Think about checking if a value is between two numbers.

Option B correctly asserts the effort is between min and max inclusive.

🔧 Debug

expert

Debugging Estimation Code Error

What error will this Python code raise when estimating test effort?

Testing Fundamentals

test_cases = ['5', '8', '3']
avg_time = 2

total = sum(test_cases) * avg_time
print(total)

A TypeError: unsupported operand type(s) for +: 'int' and 'str'

B ValueError: invalid literal for int() with base 10

C NameError: name 'avg_time' is not defined

D No error, output is 32

💡 Hint

Check the data types in the sum function.

sum() tries to add strings, causing a TypeError when adding int and str.

Practice

1. Which of the following best describes the purpose of test estimation in software testing?

easy

A. To predict the time and effort needed for testing activities

B. To write test cases for all features

C. To find all bugs in the software

D. To automate all test scripts

Solution

1. Step 1: Understand the role of test estimation

   Test estimation is used to predict how much time and effort testing will take.

2. Step 2: Compare options to the definition

   Only To predict the time and effort needed for testing activities matches this purpose; others describe different testing tasks.

3. Final Answer:

   To predict the time and effort needed for testing activities -> Option A

4. Quick Check:

   Test estimation = Predict effort [OK]

Hint: Test estimation predicts effort and time needed [OK]

Common Mistakes:

• Confusing estimation with test case design
• Thinking estimation finds bugs
• Mixing estimation with automation tasks

2. Which of the following is the correct way to describe the Work Breakdown Structure (WBS) in test estimation?

easy

A. A method to automate test scripts

B. A hierarchical decomposition of testing tasks

C. A tool to find defects automatically

D. A way to write test cases faster

Solution

1. Step 1: Define Work Breakdown Structure (WBS)

   WBS breaks down the testing work into smaller, manageable tasks in a hierarchy.

2. Step 2: Match options with WBS definition

   A hierarchical decomposition of testing tasks correctly describes WBS; others describe unrelated activities.

3. Final Answer:

   A hierarchical decomposition of testing tasks -> Option B

4. Quick Check:

   WBS = Hierarchical task breakdown [OK]

Hint: WBS breaks work into smaller tasks [OK]

Common Mistakes:

• Confusing WBS with automation tools
• Thinking WBS finds defects
• Mixing WBS with test case writing speed

3. Consider the three-point estimation technique with optimistic = 4 days, most likely = 6 days, and pessimistic = 10 days. What is the estimated time using the PERT formula?

medium

A. (4 + 6 + 10) / 3 = 7 days

B. (4 + 6 + 10) / 3 = 6.67 days

C. (4 + 4*6 + 10) / 6 = 7 days

D. (4 + 4*6 + 10) / 6 = 6.33 days

Solution

1. Step 1: Recall the PERT formula for three-point estimation

   Estimated time = (Optimistic + 4 x Most Likely + Pessimistic) / 6

2. Step 2: Calculate using given values

   (4 + 4*6 + 10) / 6 = (4 + 24 + 10) / 6 = 38 / 6 ≈ 6.33 days

3. Final Answer:

   (4 + 4*6 + 10) / 6 = 6.33 days -> Option D

4. Quick Check:

   PERT estimate = weighted average [OK]

Hint: Use PERT: (O + 4M + P) / 6 for estimate [OK]

Common Mistakes:

• Using simple average instead of weighted
• Mixing up formula order
• Incorrect multiplication factor

4. A tester used expert judgment to estimate testing time but forgot to consider test environment setup. What is the likely impact on the estimate?

medium

A. The estimate will be too low, missing setup time

B. The estimate will be too high, adding extra time

C. The estimate will be accurate regardless

D. The estimate will cause syntax errors

Solution

1. Step 1: Understand expert judgment and missing factors

   Expert judgment relies on experience; missing setup means some work is ignored.

2. Step 2: Assess impact of missing setup time

   Ignoring setup causes underestimation, so estimate is too low.

3. Final Answer:

   The estimate will be too low, missing setup time -> Option A

4. Quick Check:

   Missing tasks = underestimate [OK]

Hint: Missing tasks cause underestimation [OK]

Common Mistakes:

• Assuming estimate stays accurate without all info
• Thinking missing tasks add time automatically
• Confusing estimate errors with code errors

5. You have a testing project with tasks estimated as: Task A = 3 days, Task B = 5 days, Task C = 2 days. Using WBS, you break Task B into B1 = 2 days and B2 = 4 days. What is the correct total estimate for the project?

hard

A. 3 + 5 + 2 = 10 days

B. 3 + 5 + 2 + 4 + 2 = 16 days

C. 3 + (2 + 4) + 2 = 11 days

D. 3 + 2 + 4 = 9 days

Solution

1. Step 1: Understand WBS breakdown of Task B

   Task B is split into B1 and B2, so B's estimate is sum of B1 and B2: 2 + 4 = 6 days.

2. Step 2: Calculate total estimate

   Total = Task A + Task B (broken down) + Task C = 3 + 6 + 2 = 11 days.

3. Final Answer:

   3 + (2 + 4) + 2 = 11 days -> Option C

4. Quick Check:

   WBS sums subtasks for total [OK]

Hint: Sum subtasks in WBS for total estimate [OK]

Common Mistakes:

• Adding original Task B and subtasks together
• Ignoring subtasks and using old estimate
• Miscounting total days