What problem does it solve? Writing correct test filter expressions is error-prone because syntax differs across platforms (VSTest vs. Microsoft Testing Platform) and frameworks (MSTest, NUnit, xUnit v2/v3, TUnit). This Skill supplies the exact filter syntax for every combination so AI agents and developers select and run the right tests without guessing. ## Core Features & Use Cases - VSTest Filter Reference: Documents --filter expression syntax, operators (=, !=, ~, !~), combinators, and supported properties per framework. - MTP Filter Coverage: Details MSTest/NUnit filters, xUnit v3 framework-specific flags (--filter-class, --filter-method, --filter-trait), the xUnit query filter language, and TUnit --treenode-filter path syntax. - VSTest-to-MTP Translation: Provides a mapping table for migrating VSTest filter expressions to xUnit v3 native MTP equivalents. - Use Case: When an agent running tests needs to execute only integration tests in a specific namespace for an xUnit v3 project, it loads this reference to construct the correct --filter-namespace and --filter-trait flags. ## Quick Start Ask the AI to run only the smoke tests in your xUnit v3 project and it will use this reference to build the correct filter command.