How do I test a New File action in the NewGroup, including bringing up the Dialog, selecting the the language, checking the validation and then checking that the file is created in the correct directory? Specifically, New Elixir Module should place in Foo in foo.ex, FooBar in foo_bar.ex, Foo.Bar in foo/bar.ex. From other forum posts, I think I should be using LightCodeInsightFixtureTestCase or CodeInsightFixtureTestCase, but I don't have any fixture to start out with since I'm testing file creation. https://devnet.jetbrains.com/message/5536514#5536514 is close, but I don't have a starting file from which the new file is created. I'm sure something used so much as testing New File is somewhere in the forums or documented since every custom language plugin would need it, but I'm not having any luck with the search.