### Question:
VerifyTask extends Task<List<BisqInstaller.VerifyDescriptor>> { @Override protected List<BisqInstaller.VerifyDescriptor> call() { log.debug("VerifyTask started..."); Optional<BisqInstaller.FileDescriptor> installer = fileDescriptors.stream() .filter(fileDescriptor -> BisqInstaller.DownloadType.INSTALLER.equals(fileDescriptor.getType())) .findFirst(); if (!installer.isPresent()) { log.error("No installer file found."); return Lists.newArrayList(); } Optional<BisqInstaller.FileDescriptor> signingKeyOptional = fileDescriptors.stream() .filter(fileDescriptor -> BisqInstaller.DownloadType.SIGNING_KEY.equals(fileDescriptor.getType())) .findAny(); List<BisqInstaller.VerifyDescriptor> verifyDescriptors = Lists.newArrayList(); if (signingKeyOptional.isPresent()) { final BisqInstaller.FileDescriptor signingKeyFD = signingKeyOptional.get(); StringBuilder sb = new StringBuilder(); try { Scanner scanner = new Scanner(new FileReader(signingKeyFD.getSaveFile())); while (scanner.hasNext()) { sb.append(scanner.next()); } scanner.close(); } catch (Exception e) { log.error(e.toString()); e.printStackTrace(); BisqInstaller.VerifyDescriptor.VerifyDescriptorBuilder verifyDescriptorBuilder = BisqInstaller.VerifyDescriptor.builder(); verifyDescriptorBuilder.verifyStatusEnum(BisqInstaller.VerifyStatusEnum.FAIL); verifyDescriptors.add(verifyDescriptorBuilder.build()); return verifyDescriptors; } String signingKey = sb.toString(); List<BisqInstaller.FileDescriptor> sigs = fileDescriptors.stream() .filter(fileDescriptor -> BisqInstaller.DownloadType.SIG.equals(fileDescriptor.getType())) .collect(Collectors.toList()); for (BisqInstaller.FileDescriptor sig : sigs) { BisqInstaller.VerifyDescriptor.VerifyDescriptorBuilder verifyDescriptorBuilder = BisqInstaller.VerifyDescriptor.builder().sigFile(sig.getSaveFile()); List<BisqInstaller.FileDescriptor> keys = fileDescriptors.stream() .filter(keyDescriptor -> BisqInstaller.DownloadType.KEY.equals(keyDescriptor.getType())) .filter(keyDescriptor -> sig.getId().equals(keyDescriptor.getId())) .collect(Collectors.toList()); for (BisqInstaller.FileDescriptor key : keys) { if (signingKey.equals(key.getId())) { verifyDescriptorBuilder.keyFile(key.getSaveFile()); try { verifyDescriptorBuilder.verifyStatusEnum(BisqInstaller.verifySignature(key.getSaveFile(), sig.getSaveFile(), installer.get().getSaveFile())); updateMessage(key.getFileName()); } catch (Exception e) { verifyDescriptorBuilder.verifyStatusEnum(BisqInstaller.VerifyStatusEnum.FAIL); log.error(e.toString()); e.printStackTrace(); } verifyDescriptors.add(verifyDescriptorBuilder.build()); } else { log.trace("key not matching the defined in signingKey. We try the next."); } } } } else { log.error("signingKey is not found"); BisqInstaller.VerifyDescriptor.VerifyDescriptorBuilder verifyDescriptorBuilder = BisqInstaller.VerifyDescriptor.builder(); verifyDescriptorBuilder.verifyStatusEnum(BisqInstaller.VerifyStatusEnum.FAIL); verifyDescriptors.add(verifyDescriptorBuilder.build()); } return verifyDescriptors; } VerifyTask(final List<BisqInstaller.FileDescriptor> fileDescriptors);   }### Answer:
@Test public void call() throws Exception { }