A testing skill for examining existing code and adding small tests for normal behavior, edge cases, invalid inputs, errors, and regressions.

Use it when adding tests to an existing project, including tests for validation, boundary values, exceptions, and interactions between application layers.

It helps fill missing test coverage without writing broad or unstable tests. It also runs the relevant tests so failures and remaining gaps are visible.

add-tests — Skill for Claude Code and Codex by kousen/junie-training

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 kousen/junie-training --skill add-tests

Clone the repo

git clone --depth 1 https://github.com/kousen/junie-training

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/kousen/junie-training/add-tests/github.svg)](https://agentmods.dev/skills/kousen/junie-training/add-tests)

Your own site

<a href="https://agentmods.dev/skills/kousen/junie-training/add-tests"><img src="https://agentmods.dev/badge/skills/kousen/junie-training/add-tests/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/kousen/junie-training/add-tests"><img src="https://agentmods.dev/badge/skills/kousen/junie-training/add-tests.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 181 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.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00022	$0.00181
Opus 5.5	$0.00009	$0.00072
Sonnet 5.5	$0.00004	$0.00036
Haiku 4.5	$0.00002	$0.00018

Measured 2mo ago against content hash 892bebc407aa, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

add-tests 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 2mo 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.

.junie/skills/add-tests/SKILL.md · 27 lines

What it actually says

Add Tests

Use this skill when the request asks for missing tests, stronger coverage, or a regression test.

Workflow

Inspect the implementation and any existing tests before writing new tests.
Identify public behavior, branching logic, boundary conditions, and error paths.
Prefer small tests named by behavior.
Use parametrized tests when multiple inputs share the same expected behavior.
Avoid snapshot tests unless the project already uses them and the output is stable.
Run the relevant test command and summarize failures or coverage gaps.

Coverage Checklist

Happy path behavior
Invalid input and validation errors
Empty, null, zero, and boundary values
Exceptions and error responses
Integration points between controller/service/client layers

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.

2mo ago First seen · 27 lines · 22 tokens per session scan A 892bebc407aa

Subscribe to this mod's changes

add-tests is a skill published in the GitHub repository kousen/junie-training (12 stars, last pushed yesterday), licensed MIT. It adds 22 tokens to every session and 181 once invoked, about $0.0001 per session on Opus 5.5. 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.

Testing

research-engineer

An uncompromising Academic Research Engineer. Operates with absolute scientific rigor, objective criticism, and zero flair. Focuses on theoretical correctness, formal verification, and optimal implementation across any required technology.

davila7/claude-code-templates · 43 tokens

tika-eval-compare

Compare extracts from two Tika builds over a corpus to detect regressions in content, encoding, exceptions, and embedded-document handling. Use for "compare before/after extracts", "eval this change against the corpus".

apache/tika · 50 tokens

cua-driver

Use Cua Driver for desktop or browser tasks that are awkward or unavailable through Bash/APIs, or when the user explicitly wants GUI interaction: app testing, visual bug reproduction, form filling, calendar entry, screenshots, and demo recording. Also covers Cua setup; not OpenAI Codex Computer Use or web research.

davidondrej/skills · 68 tokens

add-tests