Test complex logic thoroughly

When implementing complex business logic, state management, or algorithms with multiple edge cases, ensure comprehensive test coverage. Complex logic is prone to bugs and difficult to reason about during code review, making tests essential for maintainability and correctness.

Focus on:

• Extract testable functions: Break down complex logic into smaller, pure functions that can be easily unit tested
• Cover edge cases: Test boundary conditions, error scenarios, and potential infinite loops
• Test state transitions: For stateful logic, verify all possible state changes and their side effects

Example from state management code:

// Instead of testing the entire complex state logic inline
initializeMessageStates: ({ inputCount, outputCount }) => {
    // Complex state calculation logic here...
}

// Extract into testable utility functions
const calculateMessageStates = (inputCount: number, outputCount: number) => {
    // Logic here - now easily testable
}

// Test the extracted function thoroughly
describe('calculateMessageStates', () => {
    it('should handle edge case where counts exceed limits', () => {
        // Test potential infinite loop scenario
    })
})

This approach makes code review easier by allowing reviewers to focus on the test cases to understand the expected behavior, rather than trying to mentally trace through complex logic paths.