void (Function<PsiClass, TypeParameterInfo[]> paramsGenerator, @NonNls String filePathBefore, @NonNls String filePathAfter) { final String filePath = DATA_PATH + filePathBefore; configureByFile(filePath); final PsiElement targetElement = TargetElementUtil.findTargetElement(getEditor(), TargetElementUtil.ELEMENT_NAME_ACCEPTED); assertTrue("<caret> is not on class name", targetElement instanceof PsiClass); PsiClass aClass = (PsiClass)targetElement; new ChangeClassSignatureProcessor(getProject(), aClass, paramsGenerator.apply(aClass)).run(); checkResultByFile(DATA_PATH + filePathAfter); }