unit-error-handling

Skill: Unit Error Handling

Load trigger: "load unit-error-handling skill" > DORA: Cap 5 (Operational Resilience) Token cost: Low

Purpose

Ensure predictable and safe error behavior across OBS and PIPE.

Responsibilities

• Validate thrown errors
• Validate error messages and codes
• Validate fallback logic
• Validate retry/backoff logic
• Validate invariant enforcement

Inputs

• Error scenarios
• Unit tests

Outputs

• error-report.json

Error Categories

Category	Test Focus	Example
Validation errors	thrown on bad input	Invalid YAML, missing fields
Network errors	retry behavior	Registry timeout, API failure
State errors	invariant enforcement	Invalid pipeline state
Resource errors	fallback logic	Missing file, unavailable service

Error Test Patterns

// Validate error thrown
expect(() => parseVersion("invalid")).toThrow("Invalid version format");

// Validate error code
try {
  await pullImage("nonexistent");
} catch (e) {
  expect(e.code).toBe("IMAGE_NOT_FOUND");
}

// Validate retry backoff
const retrySpy = jest.spyOn(client, "retry");
await client.withRetry(() => failingCall());
expect(retrySpy).toHaveBeenCalledTimes(3);

Validation Rules

• All error paths tested
• No unhandled exceptions
• No silent failures
• Error messages descriptive
• Retry logic correct

Output Format

{
  "skill": "unit-error-handling",
  "status": "pass | fail",
  "error_scenarios_tested": 25,
  "unhandled_exceptions": 0,
  "silent_failures": 0,
  "retry_tests": {
    "total": 5,
    "passing": 5
  }
}

Success Criteria

• All error paths tested
• No unhandled exceptions
• No silent failures