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 agentmods add rules/mckruz/claude-code-mastery/testinggit clone --depth 1 https://github.com/MCKRUZ/claude-code-masteryWhat 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 | $0.00432 | $0.00432 |
| Opus 5 | $0.00216 | $0.00216 |
| Sonnet 5 | $0.00086 | $0.00086 |
| Haiku 4.5 | $0.00043 | $0.00043 |
Grade A, and why
testing 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 yesterday.
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.
What it actually says
Testing
Bug Fix Workflow (MANDATORY)
When I report a bug, don't start by trying to fix it. Instead:
- Write a test that reproduces the bug (prove it fails)
- Have subagents try to fix the bug and prove it with a passing test
- The fix isn't done until the test passes This applies to all projects, always.
Coverage: 80% minimum
Unit + Integration + E2E for critical flows.
TDD (when requested)
RED (write failing test) → GREEN (minimal implementation) → REFACTOR (clean up, verify coverage)
Test Naming
- C#:
MethodName_Scenario_ExpectedResult(e.g.,Handle_InvalidRequest_ReturnsValidationFailure) - TypeScript/Angular: descriptive
it('should ...')strings - Python:
test_scenario_expected_result
Mocking Discipline
- Prefer real implementations over mocks. Use
WebApplicationFactory<Program>+ in-memory DB for integration tests. - Only mock external services (HTTP clients, third-party APIs) and time (
TimeProvider). - Never mock the thing you're testing. Never mock value objects or DTOs.
Patterns
- C#: xUnit, Arrange-Act-Assert, Moq (sparingly),
WebApplicationFactory<Program>+ in-memory DB for pipeline tests - Angular: Jasmine/Karma,
HttpTestingController,afterEach(() => httpMock.verify()) - Python: pytest, fixtures over setup methods, parametrize for variant cases
- E2E: Playwright with
data-testidselectors
Commands
- C#:
dotnet test,dotnet test --collect:"XPlat Code Coverage" - Angular:
ng test --code-coverage,ng test --watch=false --browsers=ChromeHeadless - Python:
pytest,pytest --cov - E2E:
npx playwright test
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.
- yesterday First seen · 42 lines · 432 tokens per session scan A af5ae516fbab
testing is a cursor rule published in the GitHub repository MCKRUZ/claude-code-mastery (11 stars, last pushed 4mo ago), licensed MIT. It adds 432 tokens to every session, about $0.0022 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 2026-08-30.
Other cursor rules, from other repositories
cursorrules
Cursor rule "cursorrules" from syf2211/ruledoctor, covering 订单服务项目规则（demo） and 硬性规则.
integrations
External integration rules — providers, idempotency, bulkhead, observability.
decomposition
File and folder decomposition rules — when and how to split.
architecture
FastAPI layer architecture rules — Router → Service → Repository with Protocol injection.
llm-layer
LLM provider implementation patterns.
050-plan
When the user types /plan or asks to create a project plan, feature PRD, or retrospective.