What problem does it solve? Writing tests for Avalonia UI components in this project requires knowing specific conventions: when to use [AvaloniaFact] versus [Fact], how to structure AAA-pattern tests, which assertion library to use, and how to handle headless UI limitations. This Skill encodes all those rules so generated tests match the project's established patterns. ## Core Features & Use Cases - Test attribute selection: Enforces [AvaloniaFact] for any test instantiating Avalonia controls, dialogs, or windows, and [Fact]/[Theory] for pure logic. - Control and dialog test patterns: Provides templates for value round-trips, precision transparency, constructor population from elements, explicit Save() behavior, and DialogFactory coverage. - Assertion conventions: Mandates AwesomeAssertions fluent API instead of xUnit Assert calls, with naming convention MethodUnderTest_Scenario_ExpectedBehavior. - Use Case: When adding a new EditLineDialog to the reticle editor, generate tests that verify the constructor populates controls from the element and that Save() pushes modified values back, using realistic ballistics domain data. ## Quick Start Write tests for the new MeasurementControl following the avalonia-ui-tests rules, covering initialization, value round-trip, and culture-aware parsing.
