void () { final PsiFile file = myFixture.addFileToProject("Base_Page.properties", ""); final PsiFile file2 = myFixture.addFileToProject("Base_Page_en.properties", ""); final String baseName = PropertiesUtil.getDefaultBaseName(map(Arrays.asList(file, file2), psiFile -> PropertiesImplUtil.getPropertiesFile(file))); assertEquals("Base_Page", baseName); }