### Question:
UpdaterUtil { public static Set<Certificate> readCertificates(Set<Path> certificateFilesPaths) throws CertificateException, IOException { return certificates; } private  UpdaterUtil(); static void init(boolean useDebugCerts); static Set<CertificatePair> buildCertificatePairs(String certificateDirectory, String firstCertificatePrefix,
                                                             String secondCertificatePrefix, String certificateSuffix); static Set<Certificate> readCertificates(Set<Path> certificateFilesPaths); static Certificate readCertificate(String certificateFileName); static Certificate readCertificate(Path certificatePath); static String getStringRepresentation(Certificate cert); static Set<Certificate> readCertificates(String directory, String prefix, String suffix); static Set<Certificate> readCertificates(String directory, String suffix, String... prefixes); static Set<Path> findFiles(Path directory, String prefix, String suffix); static Set<Path> findFiles(String directory, String suffix, String... prefixes); static DoubleByteArrayTuple split(byte[] arr); static Stream<Path> walk(String path); static URL getResource(String resource); static byte[] concatArrays(byte[] arr1, byte[] arr2);  }### Answer:
@Test public void testReadCertificates() throws Exception { String[] files = new String[]{"cert1", "cert2", "cert3"}; createCertificateMocksForFiles(certificateFactoryMock, files); Set<Certificate> result = UpdaterUtil.readCertificates(createPathStream(files).collect(Collectors.toSet())); assertNotNull(result); assertEquals(result.size(), files.length); HashSet<String> filenames = new HashSet<>(Arrays.asList(files)); for (Certificate certificate : result) { assertTrue(filenames.contains(certificate.toString().replace(CERTIFICATE_MOCK_PREFIX, ""))); } }