Jest Test Framework

Jest Test Framework is a skill for Claude Code, Codex from FortiumPartners/ensemble. It costs 29 tokens per session (1,131 once invoked), scanned A, original, MIT.

A testing tool for JavaScript and TypeScript projects that creates and runs Jest tests. Jest is a test framework used to check whether code behaves as expected.

In plain words
What is it for?
Use it to create unit, integration, or end-to-end tests for Node.js, Express, or React code, then run individual Jest test files.
Why use it?
It helps turn a bug report or feature description into a test and shows structured results when tests run. This reduces the manual work of writing and checking tests.

Skill for Claude CodeCodex

Written for Claude Code and Codex: user-invocable in frontmatter, but also installed under .codex/.

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is import { Button } from '../components/Button';.

Part of the ensemble-codex plugin — 40 skills shipped together

Good fit Use it to create unit, integration, or end-to-end tests for Node.js, Express, or React code, then run individual Jest test files.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/FortiumPartners/ensemble
agentmods
npx agentmods add skills/fortiumpartners/ensemble/jest

Made for: Claude Code, Codex.

Or install ensemble-codex, the plugin that ships this one along with the rest of its 40 skills.

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 Jest Test Framework

README.md
[![agentmods](https://agentmods.dev/badge/skills/fortiumpartners/ensemble/jest.svg)](https://agentmods.dev/skills/fortiumpartners/ensemble/jest)
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<a href="https://agentmods.dev/skills/fortiumpartners/ensemble/jest"><img src="https://agentmods.dev/badge/skills/fortiumpartners/ensemble/jest.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,131 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00029 $0.01131
Opus 5 $0.00015 $0.00566
Sonnet 5 $0.00006 $0.00226
Haiku 4.5 $0.00003 $0.00113

Measured 8d ago against content hash 85643fd58cce, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

Jest Test Framework 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 8d 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.

packages/codex/.codex/skills/jest/SKILL.md · 210 lines

How it starts

The opening of the file, as written. The whole thing — 210 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Jest Test Framework

Purpose

Provide comprehensive Jest test execution and generation capabilities for JavaScript and TypeScript projects, supporting:

  • Test file generation from bug reports
  • Test execution with detailed output parsing
  • Unit, integration, and E2E test patterns
  • TypeScript and modern JavaScript syntax

Usage

Generate Test File

Create a test file from a bug report or feature description:

node generate-test.js \
  --source src/components/Button.js \
  --output tests/components/Button.test.js \
  --type unit \
  --description "Button component fails to handle click events"

Execute Tests

Run Jest tests and return structured results:

node run-test.js \
  --file tests/components/Button.test.js \
  --config jest.config.js

Command Line Options

generate-test.js

  • --source <path> - Source file to test (required)
  • --output <path> - Output test file path (required)
  • --type <unit|integration|e2e> - Test type (default: unit)
  • --description <text> - Bug description or test purpose
  • --framework <react|node|express> - Framework-specific patterns

run-test.js

  • --file <path> - Test file to execute (required)
  • --config <path> - Jest config file (optional)
  • --coverage - Run with coverage report
  • --watch - Run in watch mode (not recommended for CI)

Output Format

Test Generation

Returns JSON with generated test file information:

{
  "success": true,
  "testFile": "tests/components/Button.test.js",
  "testCount": 3,
  "template": "unit-test",
  "framework": "react"
}

Test Execution

Returns JSON with test results:

{
  "success": false,
  "passed": 2,
  "failed": 1,
  "total": 3,
  "duration": 1.234,
  "failures": [
    {
      "test": "Button handles click events",
      "error": "Expected onClick to be called",
      "file": "tests/components/Button.test.js",
      "line": 15
    }
  ]
}

Templates

Unit Test Template

For testing individual functions or components in isolation:

  • Minimal dependencies
  • Fast execution
  • Focused on single responsibility

Read the full file on GitHub · 210 lines

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. 8d ago First seen · 210 lines · 29 tokens per session scan A 85643fd58cce

Subscribe to this mod's changes

Jest Test Framework is a skill published in the GitHub repository FortiumPartners/ensemble (11 stars, last pushed today), licensed MIT. It adds 29 tokens to every session and 1,131 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.