testcontainers

testcontainers is a skill for Claude Code from aks-builds/quality-skills. It costs 114 tokens per session (2,892 once invoked), scanned A, original, MIT.

A testing helper for starting real services, such as databases, message queues, and caches, in Docker containers while tests run.

In plain words
What is it for?
It helps write integration tests for services such as PostgreSQL, MongoDB, Redis, Kafka, RabbitMQ, Elasticsearch, and S3-compatible storage, across several programming languages.
Why use it?
It lets tests use the same kinds of dependencies as the application instead of relying on mocks or simplified in-memory substitutes that can hide integration problems.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the quality-skills plugin — 57 skills shipped together

Good fit It helps write integration tests for services such as PostgreSQL, MongoDB, Redis, Kafka, RabbitMQ, Elasticsearch, and S3-compatible storage, across several programming languages.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/aks-builds/quality-skills/testcontainers
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 aks-builds/quality-skills --skill testcontainers
Clone the repo
git clone --depth 1 https://github.com/aks-builds/quality-skills

Made for: Claude Code.

Or install quality-skills, the plugin that ships this one along with the rest of its 57 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 testcontainers

README.md
[![agentmods](https://agentmods.dev/badge/skills/aks-builds/quality-skills/testcontainers.svg)](https://agentmods.dev/skills/aks-builds/quality-skills/testcontainers)
Your own site
<a href="https://agentmods.dev/skills/aks-builds/quality-skills/testcontainers"><img src="https://agentmods.dev/badge/skills/aks-builds/quality-skills/testcontainers.svg" alt="Measured on agentmods" height="20"></a>
Per session 114 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,892 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 $0.00114 $0.02892
Opus 5 $0.00057 $0.01446
Sonnet 5 $0.00023 $0.00578
Haiku 4.5 $0.00011 $0.00289

Measured 8d ago against content hash 82fa6d7ec953, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

testcontainers 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.

skills/testcontainers/SKILL.md · 322 lines

How it starts

The opening of the file, as written. The whole thing — 322 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Testcontainers

You are an expert in Testcontainers — the family of libraries (originally Java, now JVM / .NET / Go / Python / Node / Rust) that lets tests spin up real Docker-backed infrastructure (databases, message queues, cache, etc.) per test class or per test method. Your goal is to help engineers replace fragile mocks / in-memory shims with real dependencies in tests while keeping the suite fast and reliable. Don't fabricate library APIs, container module names, or feature flags. When uncertain, point the reader to testcontainers.com/ or the language-specific docs.

Initial Assessment

Check .agents/qa-context.md (fallback: .claude/qa-context.md) before answering. Pay attention to:

  • Languages — Testcontainers libraries exist for JVM, .NET, Go, Python, Node, Rust, Ruby. Quality and feature parity vary.
  • What needs to be real — Postgres / MySQL / Mongo / Redis / Kafka / RabbitMQ / Elasticsearch / Localstack / S3 / etc. Pre-built modules exist for popular dependencies.
  • CI environment — Docker-in-Docker / rootless / Podman / Testcontainers Cloud. The runtime matters.
  • Test scope — integration tests (good fit), unit tests (overkill), full-system tests (Testcontainers can do it but it's a lot).
  • Existing mocks — Testcontainers often replaces in-memory fakes that have drifted from production behavior.

If the file does not exist, ask: language, dependencies under test, CI environment, existing mock strategy.


Why Testcontainers

  • Real dependency behavior — actual Postgres query planner, actual Kafka rebalance, actual Redis eviction. Catches what in-memory fakes miss.
  • Per-test isolation — each test class gets a fresh container; state doesn't leak.
  • Cross-language — same conceptual model in Java, Go, Python, Node, etc.
  • Pre-built modules — common dependencies (Postgres, Kafka, Localstack, Vault, …) have ready-made container classes.
  • Auto-cleanup via Ryuk — orphaned containers get reaped, so test failures don't leave stale containers.

Read the full file on GitHub · 322 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. 8d ago First seen · 322 lines · 114 tokens per session scan A 82fa6d7ec953

Subscribe to this mod's changes

testcontainers is a skill published in the GitHub repository aks-builds/quality-skills (2 stars, last pushed 5d ago), licensed MIT. It adds 114 tokens to every session and 2,892 once invoked, about $0.0006 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.

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