### Question:
AllureFileUtils { public static List<File> listAttachmentFiles(File... directories) { return listFilesByRegex( AllureConfig.newInstance().getAttachmentFileRegex(), directories ); } AllureFileUtils(); static TestSuiteResult unmarshal(File testSuite); static TestSuiteResult unmarshal(InputStream testSuite); static TestSuiteResult unmarshal(Reader testSuite); static List<TestSuiteResult> unmarshalSuites(File... directories); static List<File> listTestSuiteFiles(File... directories); static List<File> listAttachmentFiles(File... directories); static List<File> listFilesByRegex(String regex, File... directories); static List<File> listFiles(File[] directories, IOFileFilter fileFilter, IOFileFilter dirFilter);  }### Answer:
@Test public void ListAttachmentFilesTest() { File[] attachmentFiles = new File[]{ new File("a-attachment"), new File("b-attachment.xml") }; when(directory.listFiles(any(FileFilter.class))).thenReturn(attachmentFiles); assertThat(listAttachmentFiles(directory).size(), equalTo(attachmentFiles.length)); }