test-writer

test-writer is a skill for Claude Code, Codex from athola/skrills. It costs 14 tokens per session (179 once invoked), scanned A, original, MIT.

A tool for writing unit, integration, and end-to-end tests. It follows TDD, where tests guide development, and BDD, where behavior is described from a user's or system's point of view.

In plain words
What is it for?
Use it to test individual functions, connected components, and complete workflows, including normal cases, errors, boundaries, and external dependencies.
Why use it?
It helps catch regressions, edge cases, failures, and broken interactions before they reach users.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to test individual functions, connected components, and complete workflows, including normal cases, errors, boundaries, and external dependencies.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/athola/skrills/test-writer
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add athola/skrills --skill test-writer
Clone the repo
git clone --depth 1 https://github.com/athola/skrills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for test-writer

README.md
[![agentmods](https://agentmods.dev/badge/skills/athola/skrills/test-writer/github.svg)](https://agentmods.dev/skills/athola/skrills/test-writer)
Your own site
<a href="https://agentmods.dev/skills/athola/skrills/test-writer"><img src="https://agentmods.dev/badge/skills/athola/skrills/test-writer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for test-writer

Your own site · 80×15
<a href="https://agentmods.dev/skills/athola/skrills/test-writer"><img src="https://agentmods.dev/badge/skills/athola/skrills/test-writer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 14 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 179 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00014 $0.00179
Opus 5 $0.00007 $0.00089
Sonnet 5 $0.00003 $0.00036
Haiku 4.5 $0.00001 $0.00018

Measured 10d ago against content hash de6120424a85, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

test-writer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

assets/demo-skills/test-writer/SKILL.md · 31 lines

What it actually says

Test Writer

Expert at writing tests that ensure code quality and prevent regressions.

Test Types

  • Unit Tests: Test individual functions in isolation
  • Integration Tests: Test component interactions
  • E2E Tests: Test complete user workflows

Testing Principles

  • Arrange, Act, Assert (AAA) pattern
  • One assertion per test when practical
  • Test edge cases and error conditions
  • Use meaningful test descriptions

Coverage Guidelines

  • Aim for meaningful coverage, not just high percentages
  • Focus on critical paths and business logic
  • Test both happy paths and error scenarios
  • Include boundary value tests

Mocking Strategy

  • Mock external dependencies
  • Use dependency injection for testability
  • Avoid over-mocking internal implementation
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 31 lines · 14 tokens per session scan A de6120424a85

Subscribe to this mod's changes

test-writer is a skill published in the GitHub repository athola/skrills (69 stars, last pushed 5d ago), licensed MIT. It adds 14 tokens to every session and 179 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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