Agent skill

Add Unit Tests

Guide for adding unit tests to AReaL. An agent skill from areal-project/AReaL.

Apache-2.0Auto-check passedTesting & QA

Install Add Unit Tests

skills CLI

$ npx skills add areal-project/AReaL --skill add-unit-tests -a claude-code

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

GitHub CLI

$ gh skill install areal-project/AReaL add-unit-tests --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/areal-project/AReaL.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/add-unit-tests .claude/skills/add-unit-tests && 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/

Paste into Claude Code

Install the "add-unit-tests" agent skill from https://github.com/areal-project/AReaL/tree/main/.agents/skills/add-unit-tests into .claude/skills/add-unit-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-unit-tests", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/areal-project/AReaL/tree/main/.agents/skills/add-unit-tests

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add areal-project/AReaL --skill add-unit-tests -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install areal-project/AReaL add-unit-tests --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/areal-project/AReaL.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/add-unit-tests .agents/skills/add-unit-tests && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "add-unit-tests" agent skill from https://github.com/areal-project/AReaL/tree/main/.agents/skills/add-unit-tests into .agents/skills/add-unit-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-unit-tests", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add areal-project/AReaL --skill add-unit-tests -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install areal-project/AReaL add-unit-tests --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/areal-project/AReaL.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/add-unit-tests .cursor/skills/add-unit-tests && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "add-unit-tests" agent skill from https://github.com/areal-project/AReaL/tree/main/.agents/skills/add-unit-tests into .cursor/skills/add-unit-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-unit-tests", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/areal-project/AReaL.git --path .agents/skills/add-unit-tests

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add areal-project/AReaL --skill add-unit-tests -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install areal-project/AReaL add-unit-tests --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/areal-project/AReaL.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/add-unit-tests .gemini/skills/add-unit-tests && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "add-unit-tests" agent skill from https://github.com/areal-project/AReaL/tree/main/.agents/skills/add-unit-tests into .gemini/skills/add-unit-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-unit-tests", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install areal-project/AReaL add-unit-tests

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add areal-project/AReaL --skill add-unit-tests -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/areal-project/AReaL.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/add-unit-tests .github/skills/add-unit-tests && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "add-unit-tests" agent skill from https://github.com/areal-project/AReaL/tree/main/.agents/skills/add-unit-tests into .github/skills/add-unit-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-unit-tests", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add areal-project/AReaL --skill add-unit-tests -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install areal-project/AReaL add-unit-tests --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/areal-project/AReaL.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/add-unit-tests .opencode/skills/add-unit-tests && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "add-unit-tests" agent skill from https://github.com/areal-project/AReaL/tree/main/.agents/skills/add-unit-tests into .opencode/skills/add-unit-tests/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-unit-tests", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: add-unit-tests
GitHub stars: 5.8k
Token cost: ~1.8k tokens
SKILL.md length: 434 words
Files: 1
Skills in repo: 11
Repo updated: Oct 8, 2026
First seen: Oct 7, 2026
Licence: Apache-2.0

At a glance

Guide for adding unit tests to AReaL. An agent skill from areal-project/AReaL.

Works in 6 steps: Understand Test Types → Create Test File Structure → Write Test Functions → …
User wants to add tests for new functionality
SKILL.md covers When to Use, Step-by-Step Guide, Key Requirements (Based on… and Reference Implementations, plus 3 more sections
Calls uv, python and pytest

What it does

Add Unit Tests is an agent skill from areal-project/AReaL. Guide for adding unit tests to AReaL. Use when user wants to add tests for new functionality or increase test coverage.

Its SKILL.md is about 1.8k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Testing & QA, covering Unit testing and Test coverage. It works with pytest. The repository describes itself as: The RL Bridge for LLM-based Agent Applications. Made Simple & Flexible. The licence is Apache-2.0.

When your agent uses it

User wants to add tests for new functionality
Increase test coverage

Example prompts

“/add-unit-tests”

Requirements

Python 3

Workflow steps

6 steps, taken from the step headings in SKILL.md.

Understand Test Types
Create Test File Structure
Write Test Functions
Add Pytest Markers and CI Strategy
Mock Distributed Environment
Handle GPU Dependencies

What it can do on your machine

Read from SKILL.md and the folder at commit a642540. 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:
- uv
- python
- pytest
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use uv, which can reach the network depending on how they are called.
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

Add Unit Tests loads about 1.8k tokens when it runs. Until then it costs about 34 tokens; SKILL.md has 434 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~34
When it runs · the whole SKILL.md, loaded when a task matches: ~1.8k

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 areal-project/AReaL at commit a642540, republished under its Apache-2.0 licence (© areal-project). 434 words, ~1,755 tokens.

Download SKILL.mdSave it as .claude/skills/add-unit-tests/SKILL.md (or your agent's skills folder).

name: add-unit-tests
description: Guide for adding unit tests to AReaL. Use when user wants to add tests for new functionality or increase test coverage.

Add Unit Tests

Add unit tests to AReaL following the project's testing conventions.

When to Use

This skill is triggered when:

User asks "how do I add tests?"
User wants to increase test coverage
User needs to write tests for new functionality
User wants to understand AReaL testing patterns

Step-by-Step Guide

Step 1: Understand Test Types

AReaL has two main test categories:

Test Type	Purpose	Location Pattern	How It Runs
Unit Tests	Test individual functions/modules	`tests/test_<module>_<feature>.py`	Directly via pytest
Distributed Tests	Test distributed/parallel behavior	`tests/torchrun/run_*.py`	Via torchrun (called by pytest subprocess)

Note: All tests are invoked via pytest. Distributed tests use torchrun but are still called from pytest test files.

Step 2: Create Test File Structure

Create test file with naming convention: test_<module>_<feature>.py

python

import pytest
import torch

# Import the module to test
from areal.dataset.gsm8k import get_gsm8k_sft_dataset
from tests.utils import get_dataset_path  # Optional test utilities
# For mocking tokenizer: from unittest.mock import MagicMock

Step 3: Write Test Functions

Follow Arrange-Act-Assert pattern:

python

def test_function_under_condition_returns_expected():
    """Test that function returns expected value under condition."""
    # Arrange
    input_data = 5
    expected_output = 10

    # Act
    result = function_under_test(input_data)

    # Assert
    assert result == expected_output

Step 4: Add Pytest Markers and CI Strategy

Use appropriate pytest markers:

Marker	When to Use
`@pytest.mark.slow`	Test takes > 10 seconds (excluded from CI by default)
`@pytest.mark.ci`	Slow test that must run in CI (use with `@pytest.mark.slow`)
`@pytest.mark.asyncio`	Async test functions
`@pytest.mark.skipif(cond, reason=...)`	Conditional skip
`@pytest.mark.parametrize(...)`	Parameterized tests

CI Test Strategy:

@pytest.mark.slow: Excluded from CI by default (CI runs pytest -m "not slow")
@pytest.mark.slow + @pytest.mark.ci: Slow but must run in CI
No marker: Runs in CI (fast unit tests)

python

@pytest.mark.asyncio
async def test_async_function():
    result = await async_function()
    assert result == expected

@pytest.mark.skipif(not torch.cuda.is_available(), reason="CUDA not available")
def test_gpu_feature():
    tensor = torch.tensor([1, 2, 3], device="cuda")
    # ... assertions

@pytest.mark.parametrize("batch_size", [1, 4, 16])
def test_with_parameters(batch_size):
    # Parameterized test

@pytest.mark.slow
def test_slow_function():
    # Excluded from CI by default

@pytest.mark.slow
@pytest.mark.ci
def test_slow_but_required_in_ci():
    # Slow but must run in CI

Step 5: Mock Distributed Environment

For unit tests that need distributed mocks:

python

import torch.distributed as dist

def test_distributed_function(monkeypatch):
    monkeypatch.setattr(dist, "get_rank", lambda: 0)
    monkeypatch.setattr(dist, "get_world_size", lambda: 2)
    result = distributed_function()
    assert result == expected

Step 6: Handle GPU Dependencies

Always skip gracefully when GPU unavailable:

python

CUDA_AVAILABLE = torch.cuda.is_available()

@pytest.mark.skipif(not CUDA_AVAILABLE, reason="CUDA not available")
def test_gpu_function():
    tensor = torch.tensor([1, 2, 3], device="cuda")
    # ... assertions

Key Requirements (Based on testing.md)

Mocking Distributed

Use torch.distributed.fake_pg for unit tests
Mock dist.get_rank() and dist.get_world_size() explicitly
Don't mock internals of FSDP/DTensor

Show full SKILL.md (179 more words)Show less

GPU Test Constraints

Always skip gracefully when GPU unavailable
Clean up GPU memory: torch.cuda.empty_cache() in fixtures
Use smallest possible model/batch for unit tests

Assertions

Use torch.testing.assert_close() for tensor comparison
Specify rtol/atol explicitly for numerical tests
Avoid bare assert tensor.equal() - no useful error message

Reference Implementations

Test File	Description	Key Patterns
`tests/test_utils.py`	Utility function tests	Fixtures, parametrized tests
`tests/test_examples.py`	Integration tests with dataset loading	Dataset path resolution, success pattern matching
`tests/test_fsdp_engine_nccl.py`	Distributed tests	Torchrun integration

Common Mistakes

Missing test file registration: Ensure file follows test_*.py naming
GPU dependency without skip: Always use @pytest.mark.skipif for GPU tests
Incorrect tensor comparisons: Use torch.testing.assert_close() not assert tensor.equal()
Memory leaks in GPU tests: Clean up with torch.cuda.empty_cache()
Mocking too much: Don't mock FSDP/DTensor internals
Unclear test names: Follow test_<what>_<condition>_<expected> pattern
No docstrings: Add descriptive docstrings to test functions

Integration with Other Skills

This skill complements other AReaL development skills:

After /add-dataset: Add tests for new dataset loaders
After /add-workflow: Add tests for new workflows
After /add-reward: Add tests for new reward functions
With expert agents: Reference this skill when planning test implementation

Running Tests

bash

# First check GPU availability (many tests require GPU)
python -c "import torch; print('GPU available:', torch.cuda.is_available())"

# Run specific test file
uv run pytest tests/test_<name>.py

# Skip slow tests (CI default)
uv run pytest -m "not slow"

# Run with verbose output
uv run pytest -v

# Run distributed tests (requires torchrun and multi-GPU)
# Note: Usually invoked via pytest test files
torchrun --nproc_per_node=2 tests/torchrun/run_<test>.py

Files

Just SKILL.md in .agents/skills/add-unit-tests of areal-project/AReaL.

Open the folder on GitHubat commit a642540

Compare with similar skills

Add Unit Tests 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.

Add Unit Tests compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Add Unit Tests this skillareal-project/AReaL	5.8k	—	~1.8k	Automated safety check: Pass	Apache-2.0	yesterday
Test Coverage Reviewareed1192/finance-news-aggregator	149	—	~2.6k	Automated safety check: Pass	MIT	5 mo ago
NIC Testing Patternsnginx/kubernetes-ingress	5.1k	—	~2.8k	Automated safety check: Pass	Apache-2.0	yesterday
Squid Testing Pythoniusztinpaul/squid	203	—	~1.3k	Automated safety check: Pass	Apache-2.0	1 mo ago
Mutation Test Strength Auditbuildfastwithai/gen-ai-experiments	785	—	~641	Automated safety check: Pass	MIT	16 days ago
TDD Guidealirezarezvani/claude-skills	28k	—	~3.4k	Automated safety check: Pass	MIT	1 mo ago

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Questions about Add Unit Tests

What does Add Unit Tests do?

Guide for adding unit tests to AReaL. An agent skill from areal-project/AReaL. Add Unit Tests is an agent skill from areal-project/AReaL. Guide for adding unit tests to AReaL.

When should I use Add Unit Tests?

Add Unit Tests fits situations like: user wants to add tests for new functionality; increase test coverage.

How do I install Add Unit Tests in Claude Code?

Run `npx skills add areal-project/AReaL --skill add-unit-tests -a claude-code`. Or copy the skill folder (.agents/skills/add-unit-tests in areal-project/AReaL) into .claude/skills/add-unit-tests in your project. Claude Code loads it when a task matches its description.

How do I install Add Unit Tests in Codex?

Run `npx skills add areal-project/AReaL --skill add-unit-tests -a codex`. Or copy the skill folder (.agents/skills/add-unit-tests in areal-project/AReaL) into .agents/skills/add-unit-tests in your project. Codex loads it when a task matches its description.

Can I use Add Unit Tests 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 areal-project/AReaL --skill add-unit-tests -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/add-unit-tests, .gemini/skills/add-unit-tests, .github/skills/add-unit-tests and .opencode/skills/add-unit-tests in your project.

What does Add Unit Tests need to run?

Going by SKILL.md and its folder, Add Unit Tests needs the command-line tools its instructions call (uv, python and pytest). Our summary lists: Python 3.

Does Add Unit Tests access the network?

SKILL.md contains no URLs. Its commands use uv, which can reach the network depending on how they are called. This is read from the text; nothing was executed.

Is Add Unit Tests 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 Add Unit Tests use?

Add Unit Tests is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Add Unit Tests use?

About 1.8k tokens (SKILL.md is roughly 7k 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 Add Unit Tests?

Skills that share tags, products or a category with Add Unit Tests: Test Coverage Review (areed1192/finance-news-aggregator, 149 stars), NIC Testing Patterns (nginx/kubernetes-ingress, 5.1k stars), Squid Testing Python (iusztinpaul/squid, 203 stars) and Mutation Test Strength Audit (buildfastwithai/gen-ai-experiments, 785 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Add Unit Tests?

areal-project (a GitHub organization) maintains it in areal-project/AReaL, which has 5,817 GitHub stars. The repository holds 11 skills in this directory. The repository was last updated on October 8, 2026.

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

Install Add Unit Tests

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Add Unit Tests

When to Use

Step-by-Step Guide

Step 1: Understand Test Types

Step 2: Create Test File Structure

Step 3: Write Test Functions

Step 4: Add Pytest Markers and CI Strategy

Step 5: Mock Distributed Environment

Step 6: Handle GPU Dependencies

Key Requirements (Based on testing.md)

Mocking Distributed

GPU Test Constraints

Assertions

Reference Implementations

Common Mistakes

Integration with Other Skills

Running Tests

Files

Compare with similar skills

Similar skills

More from areal-project/AReaL

Related

Questions about Add Unit Tests