Test estimation techniques in Testing Fundamentals - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of test estimation in software testing?

Test estimation helps predict the time, effort, and resources needed to complete testing activities. It aids in planning and managing the testing process effectively.

beginner

Explain the 'Expert Judgment' technique in test estimation.

Expert Judgment relies on experienced testers or team members to estimate testing effort based on their knowledge and past experience with similar projects.

intermediate

What is the 'Work Breakdown Structure (WBS)' technique in test estimation?

WBS breaks down the testing tasks into smaller, manageable parts. Estimations are made for each part and then combined to get the total effort estimate.

intermediate

Describe the 'Three-Point Estimation' technique.

Three-Point Estimation uses three values: optimistic, pessimistic, and most likely estimates. These are combined to calculate an average estimate that accounts for uncertainty.

beginner

Why is it important to update test estimates during the project?

Updating estimates helps reflect changes in project scope, risks, or progress. It keeps the plan realistic and helps manage expectations.

Which test estimation technique uses past experience and knowledge from team members?

A Delphi Technique

B Work Breakdown Structure

C Expert Judgment

D Three-Point Estimation

Expert Judgment relies on experienced team members to estimate effort based on their knowledge.

What does the Work Breakdown Structure (WBS) technique involve?

A Ignoring task details for quick estimation

B Using three estimates to calculate an average

C Guessing based on intuition

D Breaking tasks into smaller parts and estimating each

WBS divides tasks into smaller parts to estimate effort more accurately.

In Three-Point Estimation, which of the following is NOT used?

A Pessimistic estimate

B Random estimate

C Most likely estimate

D Optimistic estimate

Three-Point Estimation uses optimistic, pessimistic, and most likely estimates, not random estimates.

Why should test estimates be updated during a project?

A To reflect changes and keep plans realistic

B To confuse the team

C To avoid doing testing

D To increase the budget unnecessarily

Updating estimates helps manage changes and keeps the project plan accurate.

Which technique involves gathering estimates anonymously from experts and reaching consensus?

A Delphi Technique

B Expert Judgment

C Work Breakdown Structure

D Three-Point Estimation

Delphi Technique collects anonymous expert opinions to reach a consensus estimate.

Describe three common test estimation techniques and when you might use each.

Think about experience, task breakdown, and handling uncertainty.

Explain why updating test estimates during a project is important and how it helps the testing process.

Consider how projects evolve over time.

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