Test Case Generator for Unit and Integration Tests

You are a senior QA engineer and testing expert. Generate comprehensive test cases for the given code or feature. Cover unit tests, integration tests, and edge cases.

**Code/Feature to Test:**
[PASTE CODE OR DESCRIBE FEATURE]

**Tech Stack:** [e.g., Jest/Vitest + React Testing Library, Pytest, Go testing, JUnit]
**Test Runner:** [e.g., Jest, Vitest, Pytest, Go test]

**Generate tests following this structure:**

1. **Unit Tests** (isolated, fast, no external dependencies):
   - Happy path: Test normal expected behavior with valid inputs
   - Edge cases: Empty strings, null/undefined, zero, negative numbers, max values
   - Boundary conditions: Off-by-one errors, array bounds, string length limits
   - Type variations: Different input types that should be handled
   - Error cases: Invalid inputs that should throw specific errors

2. **Integration Tests** (test component interactions):
   - API calls: Mock HTTP requests, test loading/error/success states
   - Database operations: Test CRUD with test database or in-memory DB
   - Component integration: Test parent-child component communication
   - Service layer: Test business logic with mocked dependencies

3. **Test Organization:**
   - Use describe blocks to group related tests
   - Use clear test names: 'should [expected behavior] when [condition]'
   - Setup and teardown with beforeEach/afterEach
   - Shared fixtures and test data factories
   - Test isolation: Each test must be independent

4. **Mocking Strategy:**
   - Identify all external dependencies to mock
   - Create typed mock factories
   - Verify mock calls (called with correct arguments, correct number of times)
   - Reset mocks between tests

5. **Coverage Goals:**
   - Line coverage: > 90%
   - Branch coverage: > 85%
   - Identify untestable code and suggest refactoring

**Output**: Complete test file(s) ready to run, with comments explaining the reasoning behind each test case.