Unit Test Deep

Q: What is a Claude Code skill and how does the Unit Test Deep skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Unit Test Deep is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Engineering category. Learn more at https://claudskills.com/learn/what-is-skill-md/.

Category: Engineering · Sub-category: testing · Last updated: 2026-06-20

Iterative test-coverage improvement loop — dispatches `/optimus:unit-test` (unit-test phase) and `/optimus:refactor` with testability focus (refactor phase) into fresh subagent contexts per cycle, applies tests, runs the test suite, bisects refactor failures, and continues until coverage plateaus or the cycle cap (default 5, hard cap 10). Use to drive coverage up on a codebase that has untestable barriers — the loop alternates between writing tests and unblocking testability so a single skill cannot stall.

Security AStatic scan found no risk patternsHow grading works ›

From the source SKILL.md

Orchestrate paired cycles of test generation and testability refactoring. Each cycle is two subagent dispatches: first /optimus:unit-test (writes tests, measures coverage, flags untestable code), then /optimus:refactor with focus on testability (unblocks the flagged items so the next cycle can cover them). All state lives in .claude/unit-test-deep-progress.json.

What this skill does

Unit Test Deep is a community-contributed Claude Code skill in the testing sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/unit-test-deep/ and loads when your prompt matches the skill's trigger.

Who uses this skill

The Unit Test Deep Claude Code skill is built for software engineers, backend developers, full-stack teams, and technical leads building and maintaining production systems. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 158,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/unit-test-deep
curl -L https://claudskills.com/skills/unit-test-deep/SKILL.md \
  -o ~/.claude/skills/unit-test-deep/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/unit-test-deep/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/unit-test-deep/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\unit-test-deep\SKILL.md on Windows. See the full install guide for step-by-step instructions.

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Unit Test Deep Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/unit-test-deep/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.

What does the Unit Test Deep skill do?

Is this skill free to install?

Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.

When should I use the Unit Test Deep skill?

Use Unit Test Deep when your Claude Code task falls under the Engineering category — specifically in the testing area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Unit Test Deep" or describe the task and let Claude pick). Browse related skills at /category/engineering/.

What is a Claude Code skill and how does the Unit Test Deep skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Unit Test Deep is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Engineering category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Source: https://github.com/oprogramadorreal/optimus-claude/blob/HEAD/skills/unit-test-deep/SKILL.md
License: MIT
Author: oprogramadorreal

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA

oprogramadorreal. (2026). Unit Test Deep [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/unit-test-deep/

BibTeX

@misc{unit-test-deep-2026,
  author    = {oprogramadorreal},
  title     = {Unit Test Deep [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/unit-test-deep/}
}

Embed this skill

Promote, attribute, or link this skill from your own README, blog post, or documentation. All three snippets are free to use — no sign-up, no API key. More distribution surfaces →

Badge

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Security scan

Grade A · scanned 2026-07-23 — free static scan against the OWASP Agentic Skills Top 10.

No risk patterns were found in any of the ten OWASP-aligned categories. How grading works ›

✓ Prompt injection
✓ Data exfiltration
✓ Supply chain
✓ Reverse shell
✓ Credentials
✓ Execution
✓ Filesystem
✓ Persistence
✓ Obfuscation
✓ Network

Show this grade on your repo (click to copy):

[![Security: A](https://img.shields.io/badge/Security-A-2e7d32)](https://claudskills.com/skills/unit-test-deep/#security)

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Part of ClaudSkills — the open registry for Claude Skills & Claude Code Skills. · What's New · Install guide · About · llms.txt

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