Test Case Writing (English)

中文版： See skill test-case-writing .

Prompt: this directory's prompts/test-case-writing_EN.md .

When to Use

• User mentions test case writing, test case design, case design

• Need to design test cases based on requirements

• Trigger examples: "Write test cases for the following requirements" or "Design test cases for login functionality"

Output Format Options

This skill defaults to Markdown (Standard-version template). To get another format, add one of the following at the end of your request:

Format Description How to request (example)

Markdown Default; good for reading and version control No extra instruction

Excel Tab-separated, paste into Excel "Please output as tab-separated table for pasting into Excel"

CSV Comma-separated, header row first "Please output as CSV"

JSON For tooling/parsing "Please output as JSON"

TestRail TestRail import format "Please output in TestRail format"

Details and examples: output-formats.md in this directory.

How to Use

• Open the relevant file in this directory's prompts/ and copy the content below the dashed line.

• Append your requirements and context (business flow, environment, constraints, acceptance criteria).

• If you need non-Markdown output, append the request sentence from output-formats.md at the end.

Reference Files

• prompts/test-case-writing_EN.md — Test case writing Standard-version prompt

• output-formats.md — Markdown / Excel / CSV / JSON request instructions

Code Examples

This skill provides the following real-world code examples:

Test Case Design Patterns (Planned) - Complete test case design examples

• Equivalence partitioning examples (10+)

• Boundary value analysis examples (8+)

• Decision table testing examples (5+)

• State transition testing examples (3+)

• Real project test case sets (50+)

Test Case Generation Tool (Coming soon)

Test Case Quality Checker (Coming soon)

Additional examples are planned in a future update.

Common Pitfalls

• ❌ Only testing happy paths → ✅ Cover normal, exception, and boundary scenarios

• ❌ Unclear test case descriptions → ✅ Use explicit steps and expected results

• ❌ Missing test data → ✅ Provide specific test data

• ❌ Inappropriate granularity → ✅ Maintain appropriate granularity, not too coarse or too fine

• ❌ Ignoring preconditions → ✅ Clearly state preconditions and environment requirements

• ❌ No priority → ✅ Mark test case priority (P0/P1/P2/P3)

• ❌ Dependencies between cases → ✅ Keep test cases independent

Best Practices

1. Test Case Structure

Standard test case format:

TC-001: Test Case Title

Priority: P0 / P1 / P2 / P3 Type: Functional / UI / Performance / Security / Compatibility Preconditions:

• Condition 1
• Condition 2

Test Steps:

1. Step 1
2. Step 2
3. Step 3

Test Data:

• Data item 1: Value
• Data item 2: Value

Expected Results:

• Result 1
• Result 2

Actual Results: [Fill during execution] Status: Pass / Fail / Blocked / Skip Notes: [Optional]

2. Test Design Methods

Equivalence Partitioning

Divide input domain into equivalence classes, select representative data from each class:

Example: Age input (valid range 18-65)

Equivalence Class Type Test Value Expected Result

< 18 Invalid 10, 17 Reject

18-65 Valid 18, 30, 65 Accept

65 Invalid 66, 100 Reject

Boundary Value Analysis

Test boundary values and values near boundaries:

Example: Age input (valid range 18-65)

Test Value Type Expected Result

17 Lower boundary-1 Reject

18 Lower boundary Accept

19 Lower boundary+1 Accept

64 Upper boundary-1 Accept

65 Upper boundary Accept

66 Upper boundary+1 Reject

Decision Table

Handle scenarios with multiple condition combinations:

Example: Login validation

Condition Rule 1 Rule 2 Rule 3 Rule 4

Username correct ✓ ✓ ✗ ✗

Password correct ✓ ✗ ✓ ✗

Result Login success Password error Username error Both error

State Transition

Test object transitions between different states:

[Not logged in] --Login--> [Logged in] --Logout--> [Not logged in] | | +----Login failed------+

3. Test Case Priority

P0 (Critical):

• Core business processes

• Blocking issues

• Must execute before each release

P1 (High):

• Important features

• Common scenarios

• Should execute before each release

P2 (Medium):

• General features

• Non-core scenarios

• Can be selectively executed

P3 (Low):

• Edge cases

• Rarely used features

• Execute when time permits

4. Test Case Writing Principles

SMART Principles:

• Specific: Steps and results are clear

• Measurable: Results are verifiable

• Achievable: Can be actually executed

• Relevant: Related to requirements

• Time-bound: Execution time is reasonable

3C Principles:

• Clear: Anyone can understand

• Concise: Not redundant

• Complete: Contains all necessary information

5. Coverage Goals

• Requirements coverage: 100% (all requirements have corresponding test cases)

• Code coverage: 80%+ (automated tests)

• Scenario coverage: Cover normal, exception, and boundary cases

• Priority distribution: P0(20%) + P1(30%) + P2(30%) + P3(20%)

Troubleshooting

Issue 1: Don't Know How to Start Writing Test Cases

Symptoms: Facing requirements document, don't know where to start

Solution:

Use 5W1H analysis method:

• What (What to test): Identify functional points

• Who (Who uses): Identify user roles

• When (When): Identify trigger conditions

• Where (Where): Identify usage scenarios

• Why (Why): Understand business goals

• How (How): Design test steps

Example:

Requirement: User login functionality

5W1H Analysis

What:

• Username password validation
• Remember me feature
• Forgot password link

Who:

• Registered users
• Unregistered users
• Administrators

When:

• First visit
• After session expires
• After active logout

Where:

• Web
• Mobile
• Different browsers

Why:

• Protect user data
• Personalized experience
• Permission control

How:

• Enter username and password
• Click login button
• Validate and redirect

Test Case Design

Based on above analysis, design following test cases:

1. Normal login (P0)
2. Username error (P1)
3. Password error (P1)
4. Remember me feature (P2)
5. Forgot password flow (P2) ...

Issue 2: Incomplete Test Coverage

Symptoms: Many missed scenarios found after testing

Solution:

Use test coverage checklist:

Test Coverage Checklist

Functional Dimension

• Normal flow
• Exception flow
• Boundary conditions
• Error handling

Data Dimension

• Valid data
• Invalid data
• Empty/null values
• Special characters
• Oversized data
• Wrong data types

User Dimension

• Different roles
• Different permissions
• Not logged in users
• Logged in users

Environment Dimension

• Different browsers
• Different operating systems
• Different screen sizes
• Different network conditions

State Dimension

• Initial state
• Intermediate state
• Final state
• Exception state

Time Dimension

• First use
• Repeated use
• Timeout scenarios
• Concurrent scenarios

Issue 3: Too Many Test Cases, Can't Execute All

Symptoms: Huge number of test cases, not enough testing time

Solution:

Priority sorting:

• Execute P0 and P1 test cases first

• P2 and P3 selectively based on time

Risk assessment:

• Increase test cases in high-risk areas

• Reduce test cases in low-risk areas

Automation:

• Automate repetitive test cases

• Manual testing focuses on exploratory testing

Test case merging:

• Merge similar test cases

• One test case validates multiple checkpoints

Example:

Before optimization (5 test cases)

TC-001: Login success TC-002: Display username after login TC-003: Display avatar after login TC-004: Display menu after login TC-005: Redirect to homepage after login

After optimization (1 test case)

TC-001: Login success and verify user information

Test Steps:

1. Enter correct username and password
2. Click login button

Expected Results:

• ✓ Login successful
• ✓ Display username
• ✓ Display user avatar
• ✓ Display navigation menu
• ✓ Redirect to homepage

Issue 4: Unclear Test Case Description

Symptoms: Others have difficulty understanding when executing test cases

Solution:

Use Given-When-Then format:

TC-001: Add product to shopping cart

Given (Preconditions):

• User is logged in
• Product stock is sufficient (> 10 items)
• Shopping cart is empty

When (Test Steps):

1. Visit product detail page
2. Select quantity: 2
3. Click "Add to Cart" button

Then (Expected Results):

• Display "Added successfully" message
• Shopping cart icon shows number 2
• Product appears in shopping cart list
• Product quantity shows 2
• Total price = Unit price × 2

Issue 5: Difficult Test Data Preparation

Symptoms: Spend a lot of time preparing data for each test case execution

Solution:

• Create test data sets:

Test Data Sets

User Data

Product Data

Use data generation tools:

• Faker.js (JavaScript)

• Faker (Python)

• Custom data generation scripts

Database snapshots:

• Save test database snapshots

• Restore snapshots before each test

Issue 6: High Test Case Maintenance Cost

Symptoms: Need to update many test cases after requirement changes

Solution:

• Modular design:

Common Steps Library

Login Steps

Step ID: COMMON-LOGIN Steps:

1. Visit login page
2. Enter username: {username}
3. Enter password: {password}
4. Click login button

Add Product to Cart

Step ID: COMMON-ADD-TO-CART Steps:

1. Visit product detail page: {product_id}
2. Select quantity: {quantity}
3. Click "Add to Cart"

Test Cases

TC-001: Purchase product flow

Steps:

1. Execute COMMON-LOGIN (username=user1, password=User123!)
2. Execute COMMON-ADD-TO-CART (product_id=P001, quantity=2)
3. Click shopping cart icon
4. Click "Checkout" button ...

• Parameterized test cases:

TC-001: Login validation (Parameterized)

Issue 7: Don't Know How to Verify Complex Expected Results

Symptoms: Expected results involve multiple systems or complex calculations

Solution:

Break down verification points:

TC-001: Order submission

Expected Results:

1. Frontend Display

• Display "Order submitted successfully" message
• Redirect to order detail page
• Order number format correct (ORD-YYYYMMDD-XXXXX)
• Order status shows "Pending payment"

2. Database Verification

• New record added to orders table
• Corresponding product records added to order_items table
• Product stock decreased by corresponding quantity
• User points increased

3. Third-party Systems

• Send order confirmation email
• Push order notification to mobile
• Sync order to ERP system

4. Log Verification

• Record order creation log
• Record stock change log
• Record points change log

Get More Help

If the issue persists:

• Check FAQ.md

• Review example README.md files

• Refer to test case templates

• Consult team's test lead

Related skills: requirements-analysis-en, functional-testing-en, test-case-reviewer-en, test-strategy-en.

Target Audience

• QA engineers and developers executing this testing domain in real projects

• Team leads who need structured, reproducible testing outputs

• AI users who need fast, format-ready deliverables for execution and reporting

Not Recommended For

• Pure production incident response without test scope/context

• Decisions requiring legal/compliance sign-off without expert review

• Requests lacking minimum inputs (scope, environment, expected behavior)

Critical Success Factors

• Provide clear scope, environment, and acceptance criteria before generation

• Validate generated outputs against real system constraints before execution

• Keep artifacts traceable (requirements -> test points -> defects -> decisions)

Output Templates and Parsing Scripts

• Template directory: output-templates/

• template-word.md (Word-friendly structure)

• template-excel.tsv (Excel paste-ready)

• template-xmind.md (XMind-friendly outline)

• template-json.json

• template-csv.csv

• template-markdown.md

• Parser scripts directory: scripts/

• Parse (generic): parse_output_formats.py

• Parse (per-format): parse_word.py , parse_excel.py , parse_xmind.py , parse_json.py , parse_csv.py , parse_markdown.py

• Convert (generic): convert_output_formats.py

• Convert (per-format): convert_to_word.py , convert_to_excel.py , convert_to_xmind.py , convert_to_json.py , convert_to_csv.py , convert_to_markdown.py

• Batch convert: batch_convert_templates.py (outputs into artifacts/ )

Examples:

python3 scripts/parse_json.py output-templates/template-json.json python3 scripts/parse_markdown.py output-templates/template-markdown.md python3 scripts/convert_to_json.py output-templates/template-markdown.md python3 scripts/convert_output_formats.py output-templates/template-json.json --to csv python3 scripts/batch_convert_templates.py --skip-same