user-story-static-verifier（用户故事静态验证器）

User Story Static Verifier

This skill helps analyze user stories statically to verify their quality, completeness, and detect common defects.

When to Use

Use this skill when you need to review or validate user stories for:

• Completeness
• Clarity
• Adherence to agile principles
• INVEST criteria (Independent, Negotiable, Valuable, Estimable, Small, Testable)
• Common requirement defects (ambiguity, omission, inconsistency, etc.)

How to Analyze a User Story

1. Check Format: Ensure it follows the standard format: "As a [role], I want [feature] so that [benefit]"
2. INVEST Criteria:

- Independent: The story should be self-contained and not depend on other stories. - Negotiable: Details should be open to discussion with stakeholders. - Valuable: The story must provide clear value to the end user. - Estimable: The effort required should be estimable by the team. - Small: The story should be small enough to complete within one sprint. - Testable: There must be clear acceptance criteria to verify completion.

1. Additional Checks:

- Acceptance Criteria: Ensure they are specific, measurable, and testable. - Clarity: Avoid ambiguous language; use clear, concise terms. - Role Definition: The "As a" part should specify a real user role. - Benefit: The "so that" part should explain the business value.

Requirement Defect Matrix

Scan user stories for these common defects:

1. Ambiguity

What it is: Use of subjective terms that can be interpreted differently by developers and QA.

Example ❌: "The system must load the report quickly."

Why it fails: What is "quickly"? 1s? 10s? Cannot be measured objectively.

Fix: "The system must load the report in under 3 seconds."

2. Omission

What it is: Missing critical information needed to develop or test the complete functionality.

Example ❌: "User can pay with credit card."

Why it fails: What card brands? What happens if it's rejected? Missing negative flow.

Fix: "User can pay with Visa, Mastercard, or Amex. If payment is rejected, display error message with reason and allow retry."

3. Inconsistency

What it is: Information within the same user story (or related stories) that contradicts itself.

Example ❌:

• Title: "Payment in Dollars only"
• Criterion: "Allow selecting Euros"

Why it fails: Title and criterion say opposite things. Total confusion.

Fix: Align title and criteria - decide on single currency or multi-currency and be consistent.

4. Inaccuracy

What it is: Incorrect, imprecise, outdated, or technically wrong information.

Example ❌: "The system should calculate an approximate 10% discount."

Why it fails: Doesn't define an exact value for comparison. How many decimals? What margin of error is acceptable?

Fix: "The system must calculate a 10% discount rounded to 2 decimal places."

5. Non-Testable

What it is: Requirements that have no logical or technical way to be verified.

Example ❌: "The interface must be beautiful and intuitive."

Why it fails: "Beautiful" is subjective. Cannot be automated or measured.

Fix: "The interface must pass WCAG 2.1 Level AA accessibility standards and complete user tasks in ≤3 clicks."

6. Scope Creep

What it is: Including unnecessary features that don't add value to the current story.

Example ❌: "When logging in, display fireworks on the screen."

Why it fails: Adds complexity and risk without clear business value.

Fix: Remove unless explicitly required for business goals. Keep stories focused on core value.

ISTQB Test Design Techniques Applicability

Verify that the user story provides sufficient information to apply standard ISTQB Foundation Level test design techniques:

Black-Box Techniques

1. Equivalence Partitioning

• Story should identify input/output domains that can be partitioned into valid and invalid classes
• Example: "User can enter age between 18-65" → Valid partition: 18-65, Invalid: <18, >65

2. Boundary Value Analysis

• Story must specify clear boundaries, ranges, or thresholds
• Example: "Password must be 8-20 characters" → Test boundaries: 7, 8, 20, 21 characters

3. Decision Tables

• Story should have multiple conditions with clear business rules
• Example: "Discount = 10% if total >$100 AND customer is VIP" → Can create decision table with combinations

4. State Transition Testing

• Story must describe state changes and transitions
• Example: "Order status: Draft → Submitted → Approved → Shipped" → Can test valid/invalid transitions

White-Box Techniques Readiness

Code Coverage

• Story should be specific enough to derive logical paths
• Acceptance criteria should cover positive and negative flows

Experience-Based Techniques

Error Guessing

• Story provides context for common error scenarios
• Example: Missing required fields, timeout scenarios, edge cases

Verification Checklist

When reviewing a user story, verify it enables:

• ✓ Clear input domains for equivalence partitioning
• ✓ Defined boundaries for boundary value analysis
• ✓ Business rules for decision table creation
• ✓ State flows for state transition testing
• ✓ Negative scenarios for comprehensive test coverage
• ✓ Measurable acceptance criteria for test oracle definition

Example: Testability Analysis

User Story: "As a customer, I want to apply a discount code so that I can reduce my order total."

ISTQB Technique Applicability:

• ❌ Equivalence Partitioning: Missing - What makes a code valid/invalid? Format? Expiration?
• ❌ Boundary Values: Missing - Any limits on code usage? Min/max discount amount?
• ❌ Decision Tables: Missing - Rules unclear (e.g., one code per order? Stackable?)
• ✓ State Transition: Possible - Code states: unused → applied → redeemed
• ⚠️ Negative scenarios: Partially - What if code is expired, invalid, or already used?

Improved Version: "As a customer, I want to apply a single-use alphanumeric discount code (5-15 chars) so that I can reduce my order total by 5-50%. The code must be valid (not expired, not previously used). If invalid, display specific error message. Only one code per order."

Now supports:

• ✓ Partitioning: Valid format (5-15 alphanumeric) vs invalid (too short, special chars, etc.)
• ✓ Boundary Values: 4, 5, 15, 16 characters; 4%, 5%, 50%, 51% discount
• ✓ Decision Tables: code valid/invalid × expired/active × used/unused combinations
• ✓ State Transition: unused → applied (if valid) → redeemed / error states
• ✓ Negative cases: expired, invalid format, already used, multiple codes

Example Analysis

User Story: "As a user, I want to login so that I can access my account."

Analysis:

• Format: ✓ Correct
• Independent: ✓ Yes
• Negotiable: ✓ Can discuss login methods
• Valuable: ✓ Access account
• Estimable: ✓ Standard login feature
• Small: ✓ Yes
• Testable: ✓ With acceptance criteria like "User enters credentials and sees dashboard"

Defect Check:

• Ambiguity: ✓ None
• Omission: ⚠️ Missing: What happens on failed login? Password requirements? Session timeout?
• Inconsistency: ✓ None
• Inaccuracy: ✓ None
• Non-Testable: ✓ Testable with proper acceptance criteria
• Scope Creep: ✓ Focused on core functionality

Recommendation: Add acceptance criteria for negative flows (failed login, account locked) and specify security requirements.

Bad Example: "The system should load data fast and look nice."

Defects Found:

• ❌ Ambiguity: "fast" and "nice" are subjective
• ❌ Omission: No user role, no benefit, missing format
• ❌ Non-Testable: Cannot measure "nice" objectively
• ❌ Inaccuracy: "fast" has no specific threshold

Fixed Version: "As a sales manager, I want the customer dashboard to load in under 2 seconds so that I can quickly access client information during calls."

When analyzing user stories, provide clear feedback on both INVEST criteria and defect detection, with actionable suggestions for improvement.