### Question:
CollisionCategoryConfig { public static Collection<CollisionCategory> imports(Xml root) { Check.notNull(root); final Collection<CollisionCategory> categories = new ArrayList<>(); if (root.hasChild(NODE_CATEGORIES)) { final Collection<Xml> childrenCategory = root.getChild(NODE_CATEGORIES).getChildren(NODE_CATEGORY); for (final Xml node : childrenCategory) { final Collection<Xml> childrenGroup = node.getChildren(TileGroupsConfig.NODE_GROUP); final Collection<CollisionGroup> groups = new ArrayList<>(childrenGroup.size()); for (final Xml group : childrenGroup) { final String name = group.getText(); groups.add(new CollisionGroup(name, new ArrayList<>(0))); } childrenGroup.clear(); final String name = node.readString(ATT_NAME); final Axis axis = Axis.valueOf(node.readString(ATT_AXIS)); final int x = node.readInteger(ATT_X); final int y = node.readInteger(ATT_Y); final boolean glue = node.readBoolean(true, ATT_GLUE); final CollisionCategory category = new CollisionCategory(name, axis, x, y, glue, groups); categories.add(category); } childrenCategory.clear(); } return categories; } private  CollisionCategoryConfig(); static Collection<CollisionCategory> imports(Xml root); static Collection<CollisionCategory> imports(Configurer configurer, MapTileCollision map); static CollisionCategory imports(Xml root, MapTileCollision map); static void exports(Xml root, CollisionCategory category); static final String NODE_CATEGORIES; static final String NODE_CATEGORY; static final String ATT_NAME; static final String ATT_AXIS; static final String ATT_X; static final String ATT_Y; static final String ATT_GLUE; }### Answer:
@Test void testNoNode() { final Xml root = new Xml("categories"); assertTrue(CollisionCategoryConfig.imports(root).isEmpty()); }