Generate Test Cases

Generate Test Cases Skill

You will analyze code and generate a list of test cases that should be written for a given method/class. This skill outputs test case descriptions only — it does NOT generate actual test code.

Target to analyze: $ARGUMENTS

Quality Standards

• Take your time to analyze the code thoroughly before listing test cases.
• Quality is more important than speed — read all relevant source files and rules carefully.
• Do not skip reading the dependency classes. Understanding the full context produces better test cases.

Instructions

Step 1: Read Rules and Analyze Context

1. Read the rules from ./rules/general/ directory (see Rules Reference below)
2. Read the target source file/class/method specified above
3. Read dependencies: Follow imports to read DTOs, entities, enums, and other types referenced by the target (as specified in code-context-analysis rule)
4. Check for existing tests: Search for existing test classes covering this target (as specified in existing-test-awareness rule) — if found, read it fully and focus only on behaviors not yet covered

Step 2: Generate Test Cases

1. Analyze ALL code branches, including:
   • Success paths
   • Error/exception paths
   • Validation logic
   • Private/protected methods called by the target
   • Security annotations (if present)
2. Apply the INCLUDE/EXCLUDE rules strictly
3. Output the list of test cases in the specified format
4. Do NOT generate actual test code — only the test case descriptions

Output Format

For each test case, provide:

## Test Cases for {ClassName}.{methodName}

### 1. {testMethodName}
- **Given:** {preconditions/input state}
- **When:** {action being tested}
- **Then:** {expected outcome}
- **Code branch:** {which code path this covers}

### 2. {testMethodName}
...

Naming Convention

Test method name format: {testedMethod}_{givenState}_{expectedOutcome}

Examples:

• calculateTotal_validProducts_returnsSum
• calculateTotal_emptyList_throwsIllegalArgumentException
• getUser_unauthorized_returns401
• getUser_forbidden_returns403

Troubleshooting

Target file not found

If the specified target does not exist, inform the user with the exact path you searched and ask for clarification.

Unsupported language

If the target code is in a language without specific rules, apply only the general rules and inform the user.

All behaviors already covered

If the existing test class already covers all identified behaviors, output a summary stating that coverage is complete. List what is already tested. Do not invent additional test cases to justify the analysis.

Example

User says: "/generate-test-cases src/main/java/com/example/service/OrderService.java"

Step 1: Agent reads rules, reads OrderService.java, reads OrderRequest.java,
        Order.java (dependencies), checks for existing OrderServiceTest.java.

Step 2: Agent outputs:

## Test Cases for OrderService.createOrder

### 1. createOrder_validRequest_savesAndReturnsOrder
- **Given:** Valid OrderRequest with productId "product-1" and quantity 5
- **When:** createOrder is called
- **Then:** Order is saved to repository and returned with generated ID
- **Code branch:** Success path

### 2. createOrder_nullProductId_throwsIllegalArgumentException
- **Given:** OrderRequest with null productId
- **When:** createOrder is called
- **Then:** IllegalArgumentException is thrown
- **Code branch:** Validation — productId null check
...

Rules Reference

CRITICAL: You MUST read and apply all rules from the following files before generating test cases:

Maintenance note: General rules in ./rules/general/ are shared with the generate-tests skill (which has copies in rules/tests/general/). When updating rules, keep both locations in sync.

General Rules (Always Apply)

• ./rules/general/test-case-generation-strategy.md - INCLUDE/EXCLUDE criteria for test cases
• ./rules/general/naming-conventions.md - Test naming format
• ./rules/general/general-principles.md - Core testing principles
• ./rules/general/what-makes-good-test.md - Clarity, Completeness, Conciseness, Resilience
• ./rules/general/keep-tests-focused.md - One scenario per test
• ./rules/general/test-behaviors-not-methods.md - Separate tests for behaviors
• ./rules/general/prefer-public-apis.md - Test public APIs over private methods
• ./rules/general/cleanly-create-test-data.md - Use helpers and builders for test data
• ./rules/general/keep-cause-effect-clear.md - Effects follow causes immediately
• ./rules/general/no-logic-in-tests.md - KISS > DRY, avoid logic in assertions
• ./rules/general/technology-stack-detection.md - Detect language and framework
• ./rules/general/verify-relevant-arguments-only.md - Only verify relevant mock arguments
• ./rules/general/existing-test-awareness.md - Check for existing tests, avoid duplicates
• ./rules/general/code-context-analysis.md - Read dependencies before analyzing