Test Estimation

Vì sao khó?

• Test effort ≠ dev effort.
• Bug fix loop unpredictable.
• Regression scope grow with codebase.

Techniques

1. Function Point (FP) based

Estimate test effort = X% dev FP. Typical X = 30-50%.

2. Test case based

• Count test cases.
• Avg time per test case (manual: 5-15 phút, automation: 15-60 phút write).
• Total = count × avg.

3. 3-point (PERT)

Estimate = (Optimistic + 4 × Most Likely + Pessimistic) / 6

4. Test point analysis (TPA)

Formal: weight + complexity factor + environment factor.

5. Historical / velocity

QA team velocity từ sprint trước (test stories completed).

Common mistakes

• Estimate only "happy path" — miss edge case, bug fix loop.
• No buffer cho environment issue, blocker.
• Forget regression suite maintenance.

Buffer math

• Test execution: 100% effort.
• Bug retest: 30%.
• Environment issue: 10%.
• Documentation: 10%.
• Total = 150% of base estimate.

VN practice

Outsourcing project FPT/KMS estimate via TPA hoặc test point — client expect quantitative. Internal startup: story-point estimation as dev.

Communication

• Show range (5-8 days), not single number.
• Track actual vs estimate → calibrate.