I'm testing references and completion and the completion results are failing based on the order of the tests because the LightPlatformCodeInsightFixtureTestCase reuses the project (and I guess the index). I tried overriding getProjectDescriptor as suggested in http://www.jetbrains.org/intellij/sdk/docs/basics/indexing_and_psi_stubs/stub_indexes.html, but my completion results were still populated with stale index entries (I know it's stale because the name didn't exist in the test path files or the configured files. The only thing that fixed the cross-test pollution was deleting the sandbox home ($HOME/Library/Caches/IntelliJIdea2016.1/plugins-sandbox). Is there a better way to ensure a new project is used between the test suites? The same project can be used for the same Test class, but I need a different one for different Test classes. Or is there a way to ask the stub index to be cleared, an equivalent of Invalidate Caches and Restart for tests?