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.
npx skills add vladolaru/claude-code-plugins --skill python-testing-patternsgit clone --depth 1 https://github.com/vladolaru/claude-code-pluginsWrote 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.
[](https://agentmods.dev/skills/vladolaru/claude-code-plugins/python-testing-patterns)<a href="https://agentmods.dev/skills/vladolaru/claude-code-plugins/python-testing-patterns"><img src="https://agentmods.dev/badge/skills/vladolaru/claude-code-plugins/python-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.
<a href="https://agentmods.dev/skills/vladolaru/claude-code-plugins/python-testing-patterns"><img src="https://agentmods.dev/badge/skills/vladolaru/claude-code-plugins/python-testing-patterns.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.01361 |
| Opus 5.5 | $0.00021 | $0.00544 |
| Sonnet 5.5 | $0.00010 | $0.00272 |
| Haiku 4.5 | $0.00005 | $0.00136 |
Grade A, and why
python-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.
How it starts
The opening of the file, as written. The whole thing — 119 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.
Python Testing Patterns
Apply these pytest patterns when writing or reviewing Python 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 |
|---|---|---|
| Python testing patterns | $SKILL_DIR/../testing-patterns/references/python-testing-patterns.md |
Full file (~430L, 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.
Python Assertion Quick Reference
| Use | Instead Of | Why |
|---|---|---|
assert x == y |
self.assertEqual(x, y) |
pytest introspection shows diff |
assert x == pytest.approx(y) |
assert x == 0.3 |
Float-safe comparison |
with pytest.raises(Exc, match=r"...") |
bare try/except |
Validates exception type + message |
mock.assert_called_once_with(...) |
mock.called_once_with(...) |
The typo silently passes (returns Mock) |
AsyncMock(return_value=...) |
Mock(return_value=...) for async |
Mock can't be awaited correctly |
@patch("using_module.fn") |
@patch("defining_module.fn") |
Patch where the name is looked up |
Mock(spec=Cls) / create_autospec(Cls) |
bare Mock() |
Catches typos and wrong signatures |
monkeypatch.setattr(...) |
direct attribute assignment | Auto-restores after test |
factory.LazyAttribute(lambda o: []) |
tags = [] at class level |
Avoids shared mutable default |
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 · 119 lines · 52 tokens per session scan A cb0ce354840e
python-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 1,361 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.
python-testing-patterns compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| python-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 |