@Override
    public MetadataNode child(String name) {
        if (name.equals("name")) {
            return new MetadataLeafNode(image.name());
        } else if (name.equals("id")) {
            return new MetadataLeafNode(image.id().toString());
        } else {
            int partitionId;
            try {
                partitionId = Integer.parseInt(name);
            } catch (NumberFormatException e) {
                return null;
            }
            PartitionRegistration registration = image.partitions().get(partitionId);
            if (registration == null) return null;
            return new MetadataLeafNode(registration.toString());
        }
    }
@Test
    public void testChildPartitionIdNull() {
        MetadataNode child1 = NODE.child("1");
        MetadataNode child2 = NODE.child("a");
        assertNull(child1);
        assertNull(child2);
    }