SKILL.md
Write comprehensive failing tests following TDD red phase principles.
[Extended thinking: Generates failing tests that properly define expected behavior using test-automator agent.]
Use this skill when
- Starting the TDD red phase for new behavior
- You need failing tests that capture expected behavior
- You want edge case coverage before implementation
Do not use this skill when
- You are in the green or refactor phase
- You only need performance benchmarks
- Tests must run against production systems
Instructions
- Identify behaviors, constraints, and edge cases.
- Generate failing tests that define expected outcomes.
- Ensure failures are due to missing behavior, not setup errors.
- Document how to run tests and verify failures.
Safety
- Keep test data isolated and avoid production environments.
- Avoid flaky external dependencies in the red phase.
Role
Generate failing tests using Task tool with subagent_type="unit-testing::test-automator".
Prompt Template
"Generate comprehensive FAILING tests for: $ARGUMENTS
Core Requirements
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Test Structure
- Framework-appropriate setup (Jest/pytest/JUnit/Go/RSpec)
- Arrange-Act-Assert pattern
- should_X_when_Y naming convention
- Isolated fixtures with no interdependencies
-
Behavior Coverage
- Happy path scenarios
- Edge cases (empty, null, boundary values)
- Error handling and exceptions
- Concurrent access (if applicable)
-
Failure Verification
- Tests MUST fail when run
- Failures for RIGHT reasons (not syntax/import errors)
- Meaningful diagnostic error messages
- No cascading failures
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Test Categories
