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.
git clone --depth 1 https://github.com/arxdsilva/vaultWrote 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/rules/arxdsilva/vault/unit-tests-tdd)<a href="https://agentmods.dev/rules/arxdsilva/vault/unit-tests-tdd"><img src="https://agentmods.dev/badge/rules/arxdsilva/vault/unit-tests-tdd/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/rules/arxdsilva/vault/unit-tests-tdd"><img src="https://agentmods.dev/badge/rules/arxdsilva/vault/unit-tests-tdd.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00427 | $0.00427 |
| Opus 5.5 | $0.00171 | $0.00171 |
| Sonnet 5.5 | $0.00085 | $0.00085 |
| Haiku 4.5 | $0.00043 | $0.00043 |
Grade A, and why
unit-tests-tdd 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 1mo 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.
What it actually says
Unit Tests & TDD
TDD (behavior changes)
For adding or changing behavior: failing unit test first → implement → refactor. Do not land production code without a red→green cycle.
File-system tests are the risky ones
File operations (list, search, copy, move, delete, watch) are where bugs cost real user data. Test these against a temp directory / in-memory fake, never the user's real file system or fixed paths on the host machine.
- Prefer an isolated temp directory per test (created and torn down by the test itself).
- Cover destructive paths explicitly: missing file, permission denied, file in use, cross-volume move, symlink/junction edge cases.
- Platform-specific behavior (trash semantics, path separators, case sensitivity) gets tested
against the adapter for that OS (see
architecture.mdc), not asserted generically.
Placement & isolation
- Go: co-located
<source>_test.go; build fixtures witht.TempDir(), never a fixed path. - Frontend (React/TS): co-locate
*.test.ts(x)next to the component/module under test. - No network access; no dependency on the host machine's real file layout or environment.
- Per
docs/SPEC.md§9: unit tests are required for the frecency ranker and path utilities; at least one e2e smoke test covers launch → search → open → preview.
Style
- Table-driven where the stack supports it, with a clear name/description per case; assert one key outcome per case.
- Parallelize test cases only when they share no mutable state (e.g. don't share a temp directory across parallel cases).
Coverage
Keep touched areas well covered (aim ≥80%); every behavior change ships with a test.
go test -race -cover ./...
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.
- 1mo ago First seen · 47 lines · 427 tokens per session scan A a57cbfc5afa1
unit-tests-tdd is a cursor rule published in the GitHub repository arxdsilva/vault (3 stars, last pushed yesterday), licensed MIT. It adds 427 tokens to every session, about $0.0017 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 2026-08-31.
Other cursor rules, from other repositories
gonavi-go
A Go coding rule set for the GoNavi repository, based on common Go style guides and the project's own conventions. It covers file structure, errors, context, concurrency, logging, and tests.
go-testing-practices
Go Testing Best Practices.
go
Idiomatic Go rules. Explicit error handling, interface-based design, context-first concurrency.
testing
Cursor rule "testing" from kanyun-inc/reskill, covering testing rules, testing philosophy, spec-driven tdd workflow, benefits of test-first approach and example: adding --dry-run option.
schema_test_implementation_guide
A concise and practical guide for building GoZod Schema test files, updated with the latest practices from stringtest.go, objecttest.go, and complextest.go.
every-error-regression-test
Mandatory regression test for every discovered defect or failure (non-negotiable).