Tdd Workflow

# Test-Driven Development Workflow

This skill ensures all code development follows TDD principles with comprehensive test coverage.

## When to Activate

- Writing new features or functionality
- Fixing bugs or issues
- Refactoring existing code
- Adding API endpoints
- Creating new components

## Core Principles

### 1. Tests BEFORE Code
ALWAYS write tests first, then implement code to make tests pass.

### 2. Coverage Requirements
- Minimum 80% coverage (unit + integration + E2E)
- All edge cases covered
- Error scenarios tested
- Boundary conditions verified

### 3. Test Types

#### Unit Tests
- Individual functions and utilities
- Component logic
- Pure functions
- Helpers and utilities

#### Integration Tests
- API endpoints
- Database operations
- Service interactions
- External API calls

#### E2E Tests (Playwright)
- Critical user flows
- Complete workflows
- Browser automation
- UI interactions

### 4. Git Checkpoints
- If the repository is under Git, create a checkpoint commit after each TDD stage
- Do not squash or rewrite these checkpoint commits until the workflow is complete
- Each checkpoint commit message must describe the stage and the exact evidence captured
- Count only commits created on the current active branch for the current task
- Do not treat commits from other branches, earlier unrelated work, or distant branch history as valid checkpoint evidence
- Before treating a checkpoint as satisfied, verify that the commit is reachable from the current `HEAD` on the active branch and belongs to the current task sequence
- The preferred compact workflow is:
  - one commit for failing test added and RED validated
  - one commit for minimal fix applied and GREEN validated
  - one optional commit for refactor complete
- Separate evidence-only commits are not required if the test commit clearly corresponds to RED and the fix commit clearly corresponds to GREEN

## TDD Workflow Steps

### Step 1: Write User Journeys
```
As a [role], I want to [action], so that [benefit]

Example:
As a user, I want to search for markets semantically,
so that I can find relevant markets even without exact keywords.
```

### Step 2: Generate Test Cases
For each user journey, create comprehensive test cases:

```typescript
describe('Semantic Search', () => {
  it('returns relevant markets for query', async () => {
    // Test implementation
  })

  it('handles empty query gracefully', async () => {
    // Test edge case
  })

  it('falls back to substring search when Redis unavailable', async () => {
    // Test fallback behavior
  })

  it('sorts results by similarity score', async () => {
    // Test sorting logic
  })
})
```

### Step 3: Run Tests (They Should Fail)
```bash
npm test
# Tests should fail - we haven't implemented yet
```

This step is mandatory and is the RED gate for all production changes.

Before modifying business logic or other production code, you must verify a valid RED state via one of these paths:
- Runtime RED:
  - The relevant test target compiles successfully
  - The new or changed test is actually executed
  - The result is RED
- Compile-time RED:
  - The new test newly instantiates, references, or exercises the buggy code path
  - The compile failure is itself the intended RED signal
- In either case, the failure is caused by the intended business-logic bug, undefined behavior, or missing implementation
- The failure is not caused only by unrelated syntax errors, broken test setup, missing dependencies, or unrelated regressions

A test that was only written but not compiled and executed does not count as RED.

Do not edit production code until this RED state is confirmed.

If the repository is under Git, create a checkpoint commit immediately after this stage is validated.
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