Testing Skill

What it does

When your agent uses it

• Running tests with --record-mode
• Verifying cassette playback
• Inspecting request/response bodies in YAML cassettes

Example prompts

• “/testing-skill”

Requirements

• Python 3
• Pre-approved tools (allowed-tools): Bash(uv run pytest *), Bash(uv run python .claude/skills/testing-skill/parse_cassette.py *), Bash(source .env && uv run pytest *), Bash(git diff *)

Workflow steps

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

1. 1Record cassettes
2. 2Verify recordings
3. 3Review snapshots

What it can do on your machine

Read from SKILL.md and the folder at commit 402a2ed. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Bash(uv run pytest *)
  • Bash(uv run python .claude/skills/testing-skill/parse_cassette.py *)
  • Bash(source .env && uv run pytest *)
  • Bash(git diff *)

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships script files (Python), which the agent can run.

  Shell commands in SKILL.md call:

  • uv
  • git

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

• Network

  Links to these hosts (documentation or services it may open):

  • github.com

  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

Testing Skill loads about 839 tokens when it runs. Until then it costs about 51 tokens; SKILL.md has 198 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~51

When it runs · the whole SKILL.md, loaded when a task matches

~839

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

• NoteMentions a .env fileSKILL.md:4

  -skill/parse_cassette.py *), Bash(source .env && uv run pytest *), Bash(git diff *)

• NoteMentions a .env fileSKILL.md:13

  - Verify `.env` exists: `test -f .env && echo 'ok' || echo 'missing'`

• NoteMentions a .env fileSKILL.md:28

  source .env && uv run pytest path/to/test.py::test_function_name -v --tb=line --record-mode=rewrite

• NoteMentions a .env fileSKILL.md:33

  source .env && uv run pytest path/to/test.py::test_one path/to/test.py::test_two -v --tb=line --record-mode=rewrite

• NoteMentions a .env fileSKILL.md:40

  source .env && uv run pytest path/to/test.py::test_function_name -vv --tb=line

• NoteMentions a .env fileSKILL.md:84

  source .env && uv run pytest tests/models/test_openai.py::test_chat_completion -v --tb=line --record-mode=rewrite

• NoteMentions a .env fileSKILL.md:87

  source .env && uv run pytest tests/models/test_openai.py::test_chat_completion -vv --tb=line

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 pydantic/pydantic-ai at commit 402a2ed, republished under its MIT licence (© pydantic). 198 words, ~839 tokens.

name

testing-skill

description

Record, rewrite, and debug VCR cassettes for HTTP recordings. Use when running tests with --record-mode, verifying cassette playback, or inspecting request/response bodies in YAML cassettes.

allowed-tools

Bash(uv run pytest *), Bash(uv run python .claude/skills/testing-skill/parse_cassette.py *), Bash(source .env && uv run pytest *), Bash(git diff *)

source .env && uv run pytest path/to/test.py::test_function_name -v --tb=line --record-mode=rewrite

source .env && uv run pytest path/to/test.py::test_one path/to/test.py::test_two -v --tb=line --record-mode=rewrite

source .env && uv run pytest path/to/test.py::test_function_name -vv --tb=line

uv run python .claude/skills/testing-skill/parse_cassette.py <cassette_path> [--interaction N]

# Parse all interactions in a cassette
uv run python .claude/skills/testing-skill/parse_cassette.py tests/models/cassettes/test_foo/test_bar.yaml

# Parse only interaction 1 (0-indexed)
uv run python .claude/skills/testing-skill/parse_cassette.py tests/models/cassettes/test_foo/test_bar.yaml --interaction 1

# 1. Record cassette
source .env && uv run pytest tests/models/test_openai.py::test_chat_completion -v --tb=line --record-mode=rewrite

# 2. Verify playback and fill snapshots
source .env && uv run pytest tests/models/test_openai.py::test_chat_completion -vv --tb=line

# 3. Review test code diffs (excludes cassettes)
git diff tests/ -- ':!**/cassettes/**'

# 4. List new/changed cassettes (name only - use parse_cassette.py to inspect)
git diff --name-only tests/ -- '**/cassettes/**'

# 5. Inspect cassette contents if needed
uv run python .claude/skills/testing-skill/parse_cassette.py tests/models/cassettes/test_openai/test_chat_completion.yaml

© pydantic, 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 1 other file in .claude/skills/testing-skill of pydantic/pydantic-ai.

• SKILL.md
• parse_cassette.py

Open the folder on GitHubat commit 402a2ed