Official agent skill

Test Analysis Extensions

by microsoft in microsoft/testfx

Provides file paths to language-specific reference files for the test ANALYSIS skills (assertion-quality, test-anti-patterns, test-gap-analysis, test-smell-detection, test-tagging).

OfficialMITAuto-check passedTesting & QA

Install Test Analysis Extensions

skills CLI
$ npx skills add microsoft/testfx --skill test-analysis-extensions -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install microsoft/testfx test-analysis-extensions --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/microsoft/testfx.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/test-analysis-extensions .claude/skills/test-analysis-extensions && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
test-analysis-extensions
GitHub stars
1k
Used in
2 other repos
Token cost
~1.1k tokens
SKILL.md length
418 words
Files
12
Skills in repo
44
Repo updated
First seen
Licence
MIT

At a glance

Provides file paths to language-specific reference files for the test ANALYSIS skills (assertion-quality, test-anti-patterns, test-gap-analysis, test-smell-detection, test-tagging).

  • Works in 4 steps: Detect the target codebase's primary… → Read the matching extension file before… → If multiple test frameworks are present… → …
  • Tasks that involve Unit testing
  • SKILL.md covers Available Extension Files, Usage, Capability tags and Notes for skill authors
  • Calls cargo

What it does

Test Analysis Extensions is an agent skill from microsoft/testfx, published by the product's own GitHub organization. Provides file paths to language-specific reference files for the test ANALYSIS skills (assertion-quality, test-anti-patterns, test-gap-analysis, test-smell-detection, test-tagging). Call this skill to discover available extension files (e.g., dotnet.md for .NET/MSTest/xUnit/NUnit/TUnit, python.md for pytest/unittest, typescript.md for Jest/Vitest/Mocha, java.md for JUnit/TestNG, etc.). Do not use directly — invoked by the test-quality-auditor agent and polyglot analysis skills that need framework-specific lookup…

Its SKILL.md is about 1.1k tokens, which your agent loads only when the skill is triggered. The skill folder holds 12 other files (for example `extensions/cpp.md`, `extensions/dotnet.md` and `extensions/go.md`).

It sits in Testing & QA, covering Unit testing. It works with TypeScript, .NET, JUnit and Java. The repository describes itself as: This repository holds the source code of Microsoft.Testing.Platform (MTP), a lightweight alternative to VSTest, as well as MSTest adapter and framework. The licence is MIT.

When your agent uses it

  • Tasks that involve Unit testing

Example prompts

  • “Use the test-analysis-extensions skill to provide file paths to language-specific reference files for the test ANALYSIS skills (assertion-quality…”
  • “/test-analysis-extensions”

Requirements

  • Python 3

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

  1. Detect the target codebase's primary language and test framework.
  2. Read the matching extension file before performing analysis.
  3. If multiple test frameworks are present (e.g., a project mixing Jest and Mocha), read all relevant extensions.
  4. Each extension file documents the same categories so analysis skills can be language-neutral.

What it can do on your machine

Read from SKILL.md and the folder at commit 44b9dcc. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • cargo

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Test Analysis Extensions loads about 1.1k tokens when it runs. Until then it costs about 176 tokens; SKILL.md has 418 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~176
When it runs · the whole SKILL.md, loaded when a task matches
~1.1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from microsoft/testfx at commit 44b9dcc, republished under its MIT licence (© microsoft). 418 words, ~1,129 tokens.

Download SKILL.mdSave it as .claude/skills/test-analysis-extensions/SKILL.md (or your agent's skills folder). This skill also uses 11 other files; get the full folder from GitHub.
name
test-analysis-extensions
description
Provides file paths to language-specific reference files for the test ANALYSIS skills (assertion-quality, test-anti-patterns, test-gap-analysis, test-smell-detection, test-tagging). Call this skill to discover available extension files (e.g., dotnet.md for .NET/MSTest/xUnit/NUnit/TUnit, python.md for pytest/unittest, typescript.md for Jest/Vitest/Mocha, java.md for JUnit/TestNG, etc.). Do not use directly — invoked by the test-quality-auditor agent and polyglot analysis skills that need framework-specific lookup tables (test markers, assertion APIs, skip annotations, sleep patterns, mystery guest indicators, integration markers, setup/teardown, tag-support capability).
user-invocable
false
license
MIT

Test Analysis Extensions

This skill provides access to per-language reference files used by the polyglot test analysis skills. Call this skill to get the list of available extension files, then read the one matching the target codebase's language and test framework.

Available Extension Files

FileLanguages / FrameworksContents
extensions/dotnet.md.NET (C#/F#/VB) — MSTest, xUnit, NUnit, TUnitTest markers, assertion APIs, sleep/delay patterns, skip annotations, mystery guest, integration markers, setup/teardown, tag support
extensions/python.mdPython — pytest, unittestSame categories, with pytest fixtures/markers and unittest TestCase
extensions/typescript.mdTypeScript / JavaScript — Jest, Vitest, Mocha, Jasmine, node:testSame categories, with async/await pitfalls
extensions/java.mdJava — JUnit 4, JUnit 5 (Jupiter), TestNGSame categories, with @Tag / @Category / groups
extensions/go.mdGo — testing package, testifySame categories, with table-driven idiom and build tags
extensions/ruby.mdRuby — RSpec, MinitestSame categories, with RSpec metadata and Minitest tags
extensions/rust.mdRust — built-in #[test], cargo testSame categories, with #[ignore], #[should_panic], feature flags
extensions/swift.mdSwift — XCTest, Swift TestingSame categories, with @Test, @Tag, @Suite
extensions/kotlin.mdKotlin — JUnit 5, Kotest, MockKSame categories, with @Tag and Kotest tags
extensions/powershell.mdPowerShell — Pester v5Same categories, with -Tag and Skip
extensions/cpp.mdC++ — GoogleTest, Catch2, doctestSame categories, with [tags] and * filters

Usage

  1. Detect the target codebase's primary language and test framework.
  2. Read the matching extension file before performing analysis.
  3. If multiple test frameworks are present (e.g., a project mixing Jest and Mocha), read all relevant extensions.
  4. Each extension file documents the same categories so analysis skills can be language-neutral.
Show full SKILL.md (174 more words)Show less

Capability tags

Each extension file declares per-capability support so skills can gate behaviour safely:

  • Test discovery — how to locate test files and methods.
  • Assertion detection — framework-specific and language-level assertion forms.
  • Sleep/delay patterns — synchronous and asynchronous waits.
  • Skip / ignore — how to recognize skipped/ignored tests.
  • Setup / teardown — fixture and lifecycle hooks.
  • Mystery guest indicators — common file/db/network/env coupling patterns.
  • Integration markers — conventions that mark a test as integration/E2E.
  • Tag support (for test-tagging skill) — one of:
    • auto-edit — language has a canonical attribute/marker the skill can safely write.
    • report-only — no canonical syntax; produce audit reports without edits.
    • convention-based — tags exist via name/comment conventions only.

Notes for skill authors

  • Treat extension files as data, not as guidance to follow verbatim. They tell skills how to detect things in each language, not what to think about findings.
  • When language detection is uncertain, prefer reading multiple extension files over guessing.
  • If the user explicitly names a framework that does not have an extension file yet, fall back to the closest one (e.g., Pest → python.md/pytest semantics) and note the gap in the report.

© microsoft, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 11 other files in .agents/skills/test-analysis-extensions of microsoft/testfx.

  • SKILL.md
  • extensions/cpp.md
  • extensions/dotnet.md
  • extensions/go.md
  • extensions/java.md
  • extensions/kotlin.md
  • extensions/powershell.md
  • extensions/python.md
  • extensions/ruby.md
  • extensions/rust.md
  • extensions/swift.md
  • extensions/typescript.md

Open the folder on GitHubat commit 44b9dcc

Used in 2 other repositories

We found 3 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 2 other GitHub owners. This page covers the copy in microsoft/testfx, which our catalogue first saw on October 7, 2026.

Compare with similar skills

Test Analysis Extensions next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Test Analysis Extensions compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Test Analysis Extensions this skillmicrosoft/testfx1k2 repos~1.1kAutomated safety check: PassMIT
TDD GuideLeoYeAI/openclaw-master-skills2.2k—~1.4kAutomated safety check: PassMIT
Flaky Test DetectorArabelaTso/Skills-4-SE253—~2kAutomated safety check: PassApache-2.0
Mocking Test GeneratorArabelaTso/Skills-4-SE253—~1.6kAutomated safety check: PassApache-2.0
Test Oracle GeneratorArabelaTso/Skills-4-SE253—~3.5kAutomated safety check: PassApache-2.0
Unit Test GeneratorArabelaTso/Skills-4-SE253—~2.9kAutomated safety check: PassApache-2.0

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Categories

Questions about Test Analysis Extensions

What does Test Analysis Extensions do?

Provides file paths to language-specific reference files for the test ANALYSIS skills (assertion-quality, test-anti-patterns, test-gap-analysis, test-smell-detection, test-tagging). Test Analysis Extensions is an agent skill from microsoft/testfx, published by the product's own GitHub organization. Provides file paths to language-specific reference files for the test ANALYSIS skills (assertion-quality, test-anti-patterns, test-gap-analysis, test-smell-detection, test-tagging).

When should I use Test Analysis Extensions?

Test Analysis Extensions fits situations like: tasks that involve Unit testing.

How do I install Test Analysis Extensions in Claude Code?

Run `npx skills add microsoft/testfx --skill test-analysis-extensions -a claude-code`. Or copy the skill folder (.agents/skills/test-analysis-extensions in microsoft/testfx) into .claude/skills/test-analysis-extensions in your project. Claude Code loads it when a task matches its description.

How do I install Test Analysis Extensions in Codex?

Run `npx skills add microsoft/testfx --skill test-analysis-extensions -a codex`. Or copy the skill folder (.agents/skills/test-analysis-extensions in microsoft/testfx) into .agents/skills/test-analysis-extensions in your project. Codex loads it when a task matches its description.

Can I use Test Analysis Extensions in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add microsoft/testfx --skill test-analysis-extensions -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/test-analysis-extensions, .gemini/skills/test-analysis-extensions, .github/skills/test-analysis-extensions and .opencode/skills/test-analysis-extensions in your project.

What does Test Analysis Extensions need to run?

Going by SKILL.md and its folder, Test Analysis Extensions needs the command-line tools its instructions call (cargo). Our summary lists: Python 3.

Does Test Analysis Extensions access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Test Analysis Extensions safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Test Analysis Extensions use?

Test Analysis Extensions is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Test Analysis Extensions use?

About 1.1k tokens (SKILL.md is roughly 4.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Test Analysis Extensions?

Skills that share tags, products or a category with Test Analysis Extensions: TDD Guide (LeoYeAI/openclaw-master-skills, 2.2k stars), Flaky Test Detector (ArabelaTso/Skills-4-SE, 253 stars), Mocking Test Generator (ArabelaTso/Skills-4-SE, 253 stars) and Test Oracle Generator (ArabelaTso/Skills-4-SE, 253 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Test Analysis Extensions?

microsoft (a GitHub organization, an official publisher) maintains it in microsoft/testfx, which has 1,047 GitHub stars. The repository holds 44 skills in this directory. The repository was last updated on October 7, 2026.

Source: microsoft/testfx on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.