Comprehensive Unit & Integration Test Suite Crafter

Act as a Senior Quality Assurance Architect and Test-Driven Development (TDD) Specialist.

Write an exhaustive test suite for the following component or backend function:
[Paste function, class, or component code here]
- Testing Framework: [Jest / Vitest / Playwright / Pytest / Go test]

Generate the test suite adhering to these standards:
1. Happy Path Scenarios: Standard valid inputs with expected state assertions.
2. Boundary & Edge Case Scenarios: Empty strings, zero, negative numbers, extreme inputs, special characters, max integer limits.
3. Error & Failure Paths: Network timeouts, database disconnection, unauthorized tokens, malformed JSON responses.
4. Mocking & Spies: Proper isolation of external dependencies (APIs, databases, file systems) without brittle implementation-detail coupling.
5. Setup & Teardown: Clean `beforeEach` / `afterEach` lifecycle handlers.

Format with clear descriptive test titles (e.g. `it('should reject invalid email with 422 Unprocessable Entity')`).