coverage-strategist

Coverage Strategist

Define pragmatic, ROI-focused test coverage strategies.

Coverage Philosophy

Goal: Maximum confidence with minimum tests

Principle: 100% coverage is not the goal. Test what matters.

Critical Path Identification

// Critical paths that MUST be tested
const criticalPaths = {
  authentication: {
    priority: "P0",
    coverage: "100%",
    paths: [
      "User login flow",
      "User registration",
      "Password reset",
      "Token refresh",
      "Session management",
    ],
    reasoning: "Security critical, impacts all users",
  },

  checkout: {
    priority: "P0",
    coverage: "100%",
    paths: [
      "Add to cart",
      "Update cart",
      "Apply coupon",
      "Process payment",
      "Order confirmation",
    ],
    reasoning: "Revenue critical, business essential",
  },

  dataIntegrity: {
    priority: "P0",
    coverage: "100%",
    paths: [
      "User data CRUD",
      "Order creation",
      "Inventory updates",
      "Database transactions",
    ],
    reasoning: "Data corruption would be catastrophic",
  },
};

// Important but not critical
const importantPaths = {
  userProfile: {
    priority: "P1",
    coverage: "80%",
    paths: ["Profile updates", "Avatar upload", "Preferences"],
    reasoning: "Important UX, but not business critical",
  },

  search: {
    priority: "P1",
    coverage: "70%",
    paths: ["Product search", "Filters", "Sorting"],
    reasoning: "Enhances experience, not essential",
  },
};

Layer-Specific Targets

# Coverage Targets by Layer

## Business Logic / Core Functions: 90-100%

**Why**: High ROI - complex logic, many edge cases
**What to test**:

- Calculations
- Validations
- State machines
- Algorithms
- Data transformations

## API Endpoints: 80-90%

**Why**: Critical integration points
**What to test**:

- Happy paths
- Error cases
- Validation
- Authentication
- Authorization

## Database Layer: 70-80%

**Why**: Data integrity matters
**What to test**:

- CRUD operations
- Transactions
- Constraints
- Migrations

## UI Components: 50-70%

**Why**: Lower ROI - visual changes, less critical
**What to test**:

- User interactions
- State changes
- Error states
- Critical flows only

## Utils/Helpers: 80-90%

**Why**: Reused everywhere, high impact
**What to test**:

- All public functions
- Edge cases
- Error handling