* Remove xunit dependency from testdriver
* swap expected/actual as needed
* Convert Test.Common to nunit
* port hosting unit tests to nunit
* port batchparser integration tests to nunit
* port testdriver.tests to nunit
* fix target to copy dependency
* port servicelayer unittests to nunit
* more unit test fixes
* port integration tests to nunit
* fix test method type
* try using latest windows build for PRs
* reduce test memory use
* Fix tools service to store the corrected file path
* Use ClientFilePath for key
* Further fixes
* Undo spacing changes
* Fix tests
* Trigger CI rebuild
* Add LanguageFlavorNotification handling and refactor LanguageService
- Added new notification handler for language flavor changed
- Refactored the LanguageService so that it no longer relies on so many intertwined static calls, which meant it was impossible to test without modifying the static instance. This will help with test reliability in the future, and prep for replacing the instance with a service provider.
* Skip if not an MSSQL doc and add test
* Handle definition requests
* Fix diagnostics handling
