test-driven-development-practices

A practical Test-Driven Development (TDD) checklist and set of examples. TDD means writing a failing test before implementing the code it checks.

In plain words
What is it for?
It guides checking test behavior, test isolation, hardcoded expected values, minimal implementations, and the Red-Green-Refactor workflow.
Why use it?
It helps prevent incomplete, unclear, or ineffective tests and encourages small, testable implementations followed by safe refactoring.

Cursor rule for Cursor

Install

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.

agentmods
npx agentmods add rules/stramp/lost-mines-phandelver/test-driven-development-practices
Clone the repo
git clone --depth 1 https://github.com/Stramp/Lost-Mines-Phandelver

Made for: Cursor.

Per session 2,049 This file is loaded in full into every session.
When invoked 2,049 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.02049 $0.02049
Opus 5 $0.01025 $0.01025
Sonnet 5 $0.00410 $0.00410
Haiku 4.5 $0.00205 $0.00205

Measured 2d ago against content hash 360ba65c5028, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

test-driven-development-practices 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 2d 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.

.cursor/rules/test-driven-development-practices.mdc · 252 lines

How it starts

The opening of the file, as written. The whole thing — 252 lines — stays where its author put it; the contents beside it link to each section on GitHub.

🧪 Test-Driven Development (TDD) - Practices

📋 Checklist TDD Obrigatório

BEFORE escrever QUALQUER código crítico, SEMPRE verificar:

  1. [ ] Escrevi o teste que falha (Red)?

    • Teste define comportamento esperado?
    • Teste pode detectar erros?
    • Teste compila (mesmo que função não exista ainda)?
  2. [ ] O teste é atômico e focado?

    • Testa uma única coisa?
    • Nome descritivo (<Scenario>_<Condition>_<ExpectedResult>)?
    • Independente de outros testes?
  3. [ ] O teste NÃO tem lógica interna?

    • Valor esperado é hardcoded (não calculado)?
    • Teste chama a função real do módulo oficial?
    • Mock apenas simula dados (não implementa lógica)?
    • Teste falharia se o código estivesse errado?
    • Não há lógica de cálculo no teste?
  4. [ ] A função será testável isoladamente?

    • Sem dependências ocultas?
    • Parâmetros claros?
    • Retorno verificável?
  5. [ ] Implementação mínima faz teste passar (Green)?

    • Solução mais simples possível?
    • Teste fica verde?
    • Comportamento básico funciona?
  6. [ ] Refatorei com segurança (Refactor)?

    • Testes ainda passam?
    • Código melhorado sem quebrar comportamento?
    • Clean Code aplicado?

Se QUALQUER resposta for NÃO → PARAR e corrigir antes de continuar

⚠️ Exceções: Quando Test-After é Aceitável

Test-After (escrever teste depois) é aceitável quando:

  • Getters/Setters simples (sem lógica)

    // Não precisa de teste primeiro
    float GetHealth() const { return Health; }
    void SetHealth(float NewHealth) { Health = NewHealth; }
    
  • Wrappers diretos de API Unreal (sem lógica customizada)

    // Wrapper simples, testar depois se necessário
    UDataTable* GetRaceDataTable() const { return RaceDataTable; }
    
  • Integração com Blueprint (testar depois pode ser mais prático)

    // Integração complexa, testar depois
    UFUNCTION(BlueprintCallable)
    void InitializeFromBlueprint(UCharacterSheetDataAsset* Asset);
    

Read the full file on GitHub · 252 lines

Changes

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.

  1. 2d ago First seen · 252 lines · 2,049 tokens per session scan A 360ba65c5028

Subscribe to this mod's changes

test-driven-development-practices is a cursor rule published in the GitHub repository Stramp/Lost-Mines-Phandelver (2 stars, last pushed 9mo ago), licensed MIT. It adds 2,049 tokens to every session, about $0.0102 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 2026-08-31.