Added some more test fixtures

[aharwood2]

This pull request introduces comprehensive improvements to the test suite for the application, focusing on increasing reliability, coverage, and robustness of both API and UI (Playwright) tests. Key enhancements include the addition of new endpoint tests for various modules, improved test setup and teardown logic, robust navigation and authentication handling for UI tests, and a mechanism to ensure the server is ready before tests run.

Test Coverage Improvements:

• Added new endpoint tests for Leave Bookings, Timesheets, Skills, and Workload Model Analysis to verify that API endpoints are accessible and return expected status codes, increasing coverage and reliability of the API test suite. [1] [2] [3] [4]

Test Infrastructure and Reliability:

• Updated the test setup in Setup.cs to wait for the application server to be ready before running tests, preventing false negatives due to server startup delays.
• Added a [OneTimeSetUp] method to BaseApiTest to ensure API test setup is performed once per test fixture.
• Introduced helper methods in BaseApiTest for generating date ranges and the current year, standardizing test parameter generation.

Playwright UI Test Suite Enhancements:

• Refactored PageLoadTests to:
  • Disable test parallelization for stability,
  • Add robust navigation with retry logic,
  • Implement automatic login handling when required,
  • Add teardown logic to clear cookies and storage between tests,
  • Parameterize page load checks for maintainability,
  • Expand coverage to all main application pages.

Dependencies and Project Configuration:

• Added explicit Using directive for Microsoft.Playwright in the test project file to ensure Playwright APIs are available.

These changes collectively make the test suite more robust, maintainable, and comprehensive, reducing flakiness and improving confidence in application quality.