mcaf-dotnet-xunit

A guide for writing, running, debugging, and repairing .NET tests that use xUnit, a testing framework for .NET applications. It covers both xUnit version 2 and version 3, including their test runners.

In plain words
What is it for?
Use it when a project uses xUnit, xunit.v3, [Fact], [Theory], or xunit.runner.visualstudio and you need to add, run, debug, or repair tests.
Why use it?
It helps avoid using the wrong packages, commands, or runner settings when a .NET project’s xUnit setup is unclear or broken.

Skill for Claude CodeCodex

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/managedcode/mcpgateway/mcaf-dotnet-xunit
Any agent
npx skills add managedcode/MCPGateway --skill mcaf-dotnet-xunit
Clone the repo
git clone --depth 1 https://github.com/managedcode/MCPGateway

Made for: Claude Code, Codex.

Per session 77 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,237 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00077 $0.01237
Opus 5 $0.00039 $0.00619
Sonnet 5 $0.00015 $0.00247
Haiku 4.5 $0.00008 $0.00124

Measured 2d ago against content hash eed59aa2387e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mcaf-dotnet-xunit 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 2d 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.

.codex/skills/mcaf-dotnet-xunit/SKILL.md · 123 lines

How it starts

The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MCAF: .NET xUnit

Trigger On

  • the repo uses xUnit v2 or xUnit v3
  • you need to add, run, debug, or repair xUnit tests
  • the team is unsure whether a project is using VSTest or Microsoft.Testing.Platform

Value

  • produce a concrete project delta: code, docs, config, tests, CI, or review artifact
  • reduce ambiguity through explicit planning, verification, and final validation skills
  • leave reusable project context so future tasks are faster and safer

Do Not Use For

  • TUnit projects
  • MSTest projects
  • generic test strategy with no xUnit-specific mechanics

Inputs

  • the nearest AGENTS.md
  • the test project file and package references
  • the active runner model for the test project

Quick Start

  1. Read the nearest AGENTS.md and confirm scope and constraints.
  2. Run this skill's Workflow through the Ralph Loop until outcomes are acceptable.
  3. Return the Required Result Format with concrete artifacts and verification evidence.

Workflow

  1. Detect the active xUnit model before changing commands:
    • xunit usually means v2
    • xunit.v3 means v3
    • xunit.runner.visualstudio plus Microsoft.NET.Test.Sdk usually means VSTest compatibility is enabled
    • TestingPlatformDotnetTestSupport or UseMicrosoftTestingPlatformRunner means Microsoft.Testing.Platform is in play
  2. Read the repo's real test command from AGENTS.md. If the repo has no explicit command yet, start with dotnet test PROJECT_OR_SOLUTION.
  3. Keep the runner model consistent:
    • xUnit v2 usually runs through VSTest
    • xUnit v3 can run as a standalone executable with dotnet run
    • xUnit v3 can also integrate with Microsoft.Testing.Platform
    • do not mix VSTest-only switches into Microsoft.Testing.Platform runs
  4. Run the narrowest useful scope first:
    • one project
    • one class
    • one trait
    • one method
  5. Prefer [Theory] for stable data-driven coverage and [Fact] for single-path invariant checks.
  6. Keep xunit.analyzers enabled when present. Fix analyzer findings instead of muting them casually.

Read the full file on GitHub · 123 lines

Files

What ships with it

1 file 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. 2d ago First seen · 123 lines · 77 tokens per session scan A eed59aa2387e

Subscribe to this mod's changes

mcaf-dotnet-xunit is a skill published in the GitHub repository managedcode/MCPGateway (5 stars, last pushed 2d ago), licensed MIT. It adds 77 tokens to every session and 1,237 once invoked, about $0.0004 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 2026-08-31.