public static void doTest(
      @NotNull final CodeInsightTestFixture fixture, @NotNull final String text) {
    PsiFile file = fixture.getFile();
    if (file == null) {
      file = fixture.addFileToProject("file.dart", text);
      fixture.openFileInEditor(file.getVirtualFile());
    } else {
      final Document document =
          FileDocumentManager.getInstance().getDocument(file.getVirtualFile());
      assert document != null;
      ApplicationManager.getApplication()
          .runWriteAction(
              new Runnable() {
                @Override
                public void run() {
                  document.setText(text);
                }
              });
    }

    doTest(fixture);
  }