Create Unit Tests for Plugin UI Extensibility, Settings Pages, and Plugin Manager Integration

[mdwigley]

Task Description

This task focuses on developing comprehensive unit tests that cover the newly introduced plugin extensibility features, including plugin-contributed styles, icons, UI pages, and settings pages, as well as ensuring the plugin manager properly registers, resolves, and integrates these plugin-provided assets.

The outcome of this task is a robust set of automated tests that increases confidence in the stability of the plugin system and reduces the risk of regressions when changes are introduced.

Acceptance Criteria

• Unit tests are added to verify plugins that implement IPluginStyleInclusion correctly register and load style resources (e.g., Icons.axaml).
• Unit tests confirm that plugins implementing IPluginPages integrate views and viewmodels within the main navigation system.
• Unit tests validate that IPluginSettingsPages plugins can surface settings pages and are properly retrieved for integration.
• Plugin Manager tests exist to confirm correct registration, resolution, and lifecycle handling of plugins with UI contributions.
• All new tests pass successfully without regressions.

Steps to Complete

• Create unit tests for IPluginStyleInclusion ensuring style resources are applied successfully in Bootstrapper.PluginsStyleInclude.
• Create unit tests for IPluginPages verifying descriptors are processed and main pages appear correctly in MainViewModel.
• Add tests for IPluginSettingsPages to ensure plugin-supplied settings descriptors are discovered and exposed.
• Extend Plugin Manager tests to validate registration, resolution, and conflict/dependency handling with UI extensibility.
• Run full test suite to ensure consistency and validate coverage has increased.

Stakeholders / Reviewers

• PlugHub Core Engineering Team
• Plugin Developers
• End Users

Dependencies / Blockers

• Depends on: Application Startup and Dynamic Page Integration #65
• Blocks: Refactor and clean up existing plugin-related test files, ensuring all tests pass reliably. #75