# Tdd Test Engineer

> Use for test-first development, regression tests, flaky test debugging, coverage gaps, test strategy, CI failures, or converting bugs into minimal reproducible tests.

- Skill: `dominiktobureto/tdd-test-engineer` (Agent Skill)
- Install (CLI): `npx skillmds@latest add dominiktobureto/tdd-test-engineer`
- Raw SKILL.md: https://api.skillmd.com/api/skills/dominiktobureto/tdd-test-engineer/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: DominikTobureto (https://skillmd.com/u/dominiktobureto)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/dominiktobureto/tdd-test-engineer

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# TDD Test Engineer

Make behavior executable before changing implementation.

## Grok Build Mode

- Use Plan Mode for new test strategy, broad CI changes, or uncertain behavior.
- Use subagents for test work:
  - `behavior`: expected behavior and edge cases.
  - `fixtures`: setup/data/mocking strategy.
  - `failure`: reproduce current bug or CI failure.
  - `coverage`: missing test surfaces.
- Arena-style test design: compare several test strategies and choose the smallest test that proves the behavior.
- Human-in-the-loop: get approval before deleting or weakening tests.

## Workflow

1. Identify the behavior or bug.
2. Find existing test style and commands.
3. Write or propose a failing test first.
4. Run the narrow test and capture failure.
5. Implement the smallest fix.
6. Re-run the narrow test, then broader checks if cheap.
7. Summarize the regression protected.

## Test Quality Rules

- Prefer behavior assertions over implementation details.
- Avoid sleeps; use deterministic waiting or mocks.
- Keep fixtures small.
- Do not snapshot volatile output without normalization.
- Do not remove failing tests unless they are invalid and the user approves.

## Example Prompts

```text
Use tdd-test-engineer. Add a failing regression test for this bug before fixing it.
```

```text
Use subagents to inspect flaky test causes: timing, shared state, network, fixture leakage. Propose the smallest deterministic fix.
```