What is rust-testing-patterns?

A collection of patterns for writing and reviewing Rust tests. It covers Rust's built-in test tools along with async tests, test doubles, property-based tests, snapshots, and benchmarks.

Use it when writing or reviewing Rust tests, testing asynchronous code, using mocks, checking many generated inputs, comparing snapshots, or measuring performance.

It helps you choose suitable Rust testing techniques and spot tests that are fragile or poorly isolated. It also supports behavior-focused testing rather than checking implementation details.

rust-testing-patterns — Skill for Claude Code by vladolaru

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 vladolaru/claude-code-plugins --skill rust-testing-patterns

Clone the repo

git clone --depth 1 https://github.com/vladolaru/claude-code-plugins

Made for: Claude Code.

Or install pirategoat-tools, the plugin that ships this one along with the rest of its 22 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/vladolaru/claude-code-plugins/rust-testing-patterns/github.svg)](https://agentmods.dev/skills/vladolaru/claude-code-plugins/rust-testing-patterns)

Your own site

<a href="https://agentmods.dev/skills/vladolaru/claude-code-plugins/rust-testing-patterns"><img src="https://agentmods.dev/badge/skills/vladolaru/claude-code-plugins/rust-testing-patterns/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/vladolaru/claude-code-plugins/rust-testing-patterns"><img src="https://agentmods.dev/badge/skills/vladolaru/claude-code-plugins/rust-testing-patterns.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,391 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. Third-party audits

NVIDIA SkillSpector pass 7 Sept 2026

How audits are shown

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	$0.00052	$0.01391
Opus 5.5	$0.00021	$0.00556
Sonnet 5.5	$0.00010	$0.00278
Haiku 4.5	$0.00005	$0.00139

Measured 2mo ago against content hash d60408a07d56, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

rust-testing-patterns 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.

plugins/pirategoat-tools/skills/rust-testing-patterns/SKILL.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Directory

Resolve SKILL_DIR to the absolute directory containing this SKILL.md, as shown by the current host, before using any bundled path below. Before a shell command uses $SKILL_DIR, assign it in that command or replace it with the resolved path. It is not a host-exported environment variable.

Rust Testing Patterns

Apply these Rust testing patterns when writing or reviewing tests. Flag red flags during review. Use the assertion quick reference when writing assertions. For shared test quality principles (philosophy, smells, mocking decisions), see testing-patterns.

Reference Routing

Need	Reference File	Sections to Read
Rust testing patterns	`$SKILL_DIR/../testing-patterns/references/rust-testing-patterns.md`	Full file (~350L, manageable)
Behavior vs implementation	`$SKILL_DIR/../testing-patterns/references/test-philosophy.md`	`## The Fundamental Shift` + `## Four Core Principles`
Flaky/brittle tests	`$SKILL_DIR/../testing-patterns/references/test-smells.md`	`## The Six Major Test Smells` (relevant subsection)
Mock usage decisions	`$SKILL_DIR/../testing-patterns/references/mocking-strategies.md`	`## The Mocking Decision Framework`
AAA pattern/naming	`$SKILL_DIR/../testing-patterns/references/test-structure.md`	`## The AAA Pattern` + `## Test Naming Conventions`
Test data strategy	`$SKILL_DIR/../testing-patterns/references/test-data.md`	`## Factories` + `## Builders`

How to read sections: Grep for heading to find line number, Read with offset+limit.

Rust Assertion Quick Reference

Use	Instead Of	Why
`assert_eq!(got, want)`	`assert!(got == want)`	Diff output on failure
`assert!(result.is_err())`	`#[should_panic]`	Explicit, no false positives
`result.unwrap_err()` + assert	`#[should_panic(expected = "...")]`	Better failure messages
`prop_assert!(expr)`	`assert!(expr)` in proptest	Integrates with shrinking
`tempfile::TempDir`	`fs::create_dir("/tmp/...")`	RAII cleanup, no collisions
`#[serial]`	`-- --test-threads=1`	Granular, per-resource isolation
`#[tokio::test(flavor = "multi_thread")]`	`#[tokio::test]` for concurrency	Catches race conditions

Read the full file on GitHub · 118 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.

2mo ago First seen · 118 lines · 52 tokens per session scan A d60408a07d56

Subscribe to this mod's changes

rust-testing-patterns is a skill published in the GitHub repository vladolaru/claude-code-plugins (8 stars, last pushed 5d ago), licensed MIT. It adds 52 tokens to every session and 1,391 once invoked, about $0.0002 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 2026-09-03.

Testing Unit testing

rust-testing-patterns next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
rust-testing-patternsvladolaru/claude-code-plugins	Skill	8	5d ago	MIT	A	52	Claude Code
test-masterJeffallan/claude-skills	Skill	12k	12d ago	MIT	A	104	Claude Code
migrate-xunit-to-xunit-v3dotnet/skills	Skill	5.9k	today	MIT	A	149	Claude Code
go-testingGentleman-Programming/gentle-ai	Skill	8.8k	yesterday	MIT	A	26	Claude Code, Codex
principle-test-behavior-not-implementationmichael-denyer/pstack-claude	Skill	4.2k	today	MIT	A	50	Claude Code
dart-testdartsim/dart	Skill	1.2k	yesterday	BSD-2-Clause	A	18	Claude Code, Codex
test-generatorrshankras/claude-code-apple-skills	Skill	881	2d ago	MIT	A	33	Claude Code