### Question:
GlusterPath implements Path { @Override public Path getRoot() { if (absolute) { return fileSystem.getRootDirectories().iterator().next(); } else { return null; } } GlusterPath(GlusterFileSystem fileSystem, String path);   GlusterPath(GlusterFileSystem fileSystem, String[] parts, boolean absolute); @Override boolean isAbsolute(); @Override Path getRoot(); @Override Path getFileName(); @Override Path getParent(); @Override int getNameCount(); @Override Path getName(int i); @Override Path subpath(int i, int i2); @Override boolean startsWith(Path path); @Override boolean startsWith(String s); @Override boolean endsWith(Path path); @Override boolean endsWith(String s); @Override Path normalize(); @Override Path resolve(Path path); @Override Path resolve(String s); @Override Path resolveSibling(Path path); @Override Path resolveSibling(String s); @Override Path relativize(Path path); @Override URI toUri(); @Override Path toAbsolutePath(); @Override Path toRealPath(LinkOption... linkOptions); @Override File toFile(); @Override WatchKey register(WatchService watchService, WatchEvent.Kind<?>[] kinds, WatchEvent.Modifier... modifiers); @Override WatchKey register(WatchService watchService, WatchEvent.Kind<?>... kinds); @Override Iterator<Path> iterator(); @Override int compareTo(Path path); String toString(); String getString();  }### Answer:
@Test public void testGetRoot_absolute() { List<Path> paths = new LinkedList<Path>(); GlusterPath root = new GlusterPath(mockFileSystem, "/"); paths.add(root); doReturn(paths).when(mockFileSystem).getRootDirectories(); Path p = new GlusterPath(mockFileSystem, "/foo/bar"); Path returned = p.getRoot(); verify(mockFileSystem).getRootDirectories(); assertEquals(root, returned); }
@Test public void testGetRoot_relative() { Path p = new GlusterPath(mockFileSystem, "foo/bar"); Path returned = p.getRoot(); verify(mockFileSystem, times(0)).getRootDirectories(); assertEquals(null, returned); }