test-harness

test-harness is a skill for Claude Code from Mathews-Tom/armory. It costs 65 tokens per session (2,799 once invoked), scanned A, original, MIT.

A tool that generates pytest test suites from Python code, including normal cases, boundary cases, errors, asynchronous code, fixtures, and mocks. pytest is a Python framework for running automated tests.

In plain words
What is it for?
Use it to create unit tests for Python functions and services, including dependency mocks, reusable fixtures, and async test cases.
Why use it?
It reduces the effort of designing broad test coverage and setting up the supporting test code.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions CLAUDE.md.

Part of the armory plugin — 85 skills, 1 agent shipped together

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.

agentmods
npx agentmods add skills/mathews-tom/armory/test-harness
Any agent
npx skills add Mathews-Tom/armory --skill test-harness
Clone the repo
git clone --depth 1 https://github.com/Mathews-Tom/armory

Made for: Claude Code.

Or install armory, the plugin that ships this one along with the rest of its 85 skills, 1 agent.

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-harness

README.md
[![agentmods](https://agentmods.dev/badge/skills/mathews-tom/armory/test-harness.svg)](https://agentmods.dev/skills/mathews-tom/armory/test-harness)
Your own site
<a href="https://agentmods.dev/skills/mathews-tom/armory/test-harness"><img src="https://agentmods.dev/badge/skills/mathews-tom/armory/test-harness.svg" alt="Measured on agentmods" height="20"></a>
Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,799 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
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 $0.00065 $0.02799
Opus 5 $0.00032 $0.01399
Sonnet 5 $0.00013 $0.00560
Haiku 4.5 $0.00006 $0.00280

Measured yesterday against content hash b5b4ef5496b9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

test-harness scanned grade A with 1 finding 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 yesterday.

The scan reads SKILL.md. This mod also ships 1 executable file (evals/fixtures/sample_module.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

not at the definition site. `@patch('mymodule.requests.get')`, not
skills/test-harness/SKILL.md · 263 lines

How it starts

The opening of the file, as written. The whole thing — 263 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Test Harness

Systematic test suite generation that transforms source code into comprehensive, runnable pytest files. Analyzes function signatures, dependency graphs, and complexity hotspots to produce tests covering happy paths, boundary conditions, error states, and async flows — with properly scoped fixtures and focused mocks.

Reference Files

File Contents Load When
references/pytest-patterns.md Fixture scopes, parametrize, marks, conftest layout, built-in fixtures Always
references/mock-strategies.md Mock decision tree, patch boundaries, assertions, anti-patterns Target has external dependencies
references/async-testing.md pytest-asyncio modes, event loop fixtures, async mocking Target contains async code
references/fixture-design.md Factory fixtures, yield teardown, scope selection, composition Test requires non-trivial setup
references/coverage-targets.md Threshold table, branch vs line, pytest-cov config, exclusion patterns Coverage assessment requested

Prerequisites

  • pytest >= 7.0
  • Python >= 3.10
  • pytest-asyncio — required only when generating async tests
  • pytest-mock — optional, provides mocker fixture as alternative to unittest.mock

Workflow

Phase 1: Reconnaissance

Before writing a single test, build a model of the target code:

  1. Identify scope — What functions, classes, or modules need tests? If unspecified, check for recent modifications: git diff --name-only HEAD~5
  2. Read function signatures — Parameters, types, return types, defaults. Every parameter is a test dimension.
  3. Map dependencies — Which calls go to external systems (DB, API, filesystem, clock)? These are mock candidates.
  4. Detect complexity hotspots — Functions with high branch counts, deep nesting, or multiple return paths need more test cases.
  5. Check existing tests — If tests already exist, understand what they cover. Do not duplicate; extend.
  6. Read project conventions — Check CLAUDE.md, conftest.py, pytest.ini/pyproject.toml for fixtures, markers, and test organization patterns already in use.

Read the full file on GitHub · 263 lines

Files

What ships with it

7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday First seen · 263 lines · 65 tokens per session scan A b5b4ef5496b9

Subscribe to this mod's changes

test-harness is a skill published in the GitHub repository Mathews-Tom/armory (316 stars, last pushed yesterday), licensed MIT. It adds 65 tokens to every session and 2,799 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-05.