### Question:
SignsDir extends VirtualContainer { public SignDir newSignDir() { String name = SignDir.SignContainerPrefix + maxSignIndex; maxSignIndex++; return this.obtainContainer(name, SignDir::new); } SignsDir(Path fullDir); Signatures getSignatures(); SignsDir setSignatures(Signatures signatures); SignDir newSignDir(); SignDir getByIndex(Integer index); SignDir getSignDir(String containerName); static final String SignaturesFileName; }### Answer:
@Test void newSignDir() throws IOException { Path root = Paths.get("target/Signs"); if (Files.exists(root)) { FileUtils.deleteDirectory(root.toFile()); } Files.createDirectory(root); SignsDir signsDir = new SignsDir(root); SignDir signDir = signsDir.newSignDir(); assertEquals("Sign_0", signDir.getContainerName()); }