add unit tests with documentation for 8 previously untested components

[codomposer]

---

name: Pull Request
about: Create a pull request to improve this repository
title: "test: add unit tests with documentation for 8 previously untested components"
labels: "testing"
assignees: ""

Description

Linked issue: N/A

Problem
Several core components in the react-datepicker library lacked dedicated unit tests, making it difficult to:

• Verify component behavior and prevent regressions
• Understand component functionality through test documentation
• Maintain code quality and confidence during refactoring
• Ensure accessibility features work correctly

The following components had no test coverage:

• CalendarContainer - Accessibility wrapper
• ClickOutsideWrapper - Click detection utility
• Portal - DOM portal rendering
• TabLoop - Keyboard navigation management
• withFloating - Higher-Order Component for Floating UI
• PopperComponent - Component orchestration
• MonthDropdownOptions - Month selection dropdown
• Year - Year picker component

Changes
Added comprehensive unit tests for 8 previously untested components:

1. calendar_container_test.test.tsx (78 lines)

   • Tests ARIA attributes and accessibility features
   • Verifies time selection modes
   • Tests custom className and HTML attribute passthrough

2. click_outside_wrapper_test.test.tsx (252 lines)

   • Tests click detection (inside vs outside)
   • Tests ignore class functionality
   • Tests event listener cleanup and memory leak prevention
   • Tests Shadow DOM support with composed events
   • Tests ref forwarding and dynamic handler updates

3. portal_test.test.tsx (218 lines)

   • Tests portal creation and rendering
   • Tests automatic portal root creation and reuse
   • Tests Shadow DOM support
   • Tests cleanup on unmount
   • Tests multiple independent portals

4. tab_loop_test.test.tsx (297 lines)

   • Tests tab loop creation with start/end sentinels
   • Tests focus management (first/last element cycling)
   • Tests disabled element handling
   • Tests various focusable element types
   • Tests enable/disable functionality

5. with_floating_test.test.tsx (226 lines)

   • Tests HOC wrapping and prop passthrough
   • Tests Floating UI integration
   • Tests display name generation
   • Tests middleware, placement, and autoUpdate

6. popper_component_test.test.tsx (324 lines)

   • Tests target and popper rendering
   • Tests portal and TabLoop integration
   • Tests arrow rendering
   • Tests keyboard event handling
   • Tests Shadow DOM support

7. month_dropdown_options_test.test.tsx (373 lines)

   • Tests month option rendering and selection
   • Tests keyboard navigation (Enter, Escape, Arrow keys)
   • Tests wrap-around behavior
   • Tests ARIA attributes and accessibility

8. year_test.test.tsx (557 lines)

   • Tests year range rendering
   • Tests keyboard navigation
   • Tests range selection visualization
   • Tests disabled years (minDate, maxDate, filters)
   • Tests ARIA attributes and accessibility

Documentation improvements:

• Added comprehensive JSDoc comments to test suites explaining component purpose
• Added test-level comments describing what each test verifies
• Added inline comments for complex logic

Screenshots

N/A - This PR adds test coverage only

To reviewers

• All tests follow the existing project patterns using @testing-library/react and Jest
• Tests include comprehensive coverage of rendering, user interactions, keyboard navigation, and accessibility
• Mock implementations are used for external dependencies (Floating UI, Portal, TabLoop) to isolate component logic
• TypeScript lint errors in IDE are expected (missing type definitions) but do not affect test execution
• All tests pass successfully with yarn test

Test execution:

yarn test  # Run all tests
yarn test:ci  # Run with coverage

Contribution checklist

• I have followed the contributing guidelines.
• I have added sufficient test coverage for my changes.
• I have formatted my code with Prettier and checked for linting issues with ESLint for code readability.