require 'test_helper' class Note < ActiveRecord::Base acts_as_nested_set :scope => [:notable_id, :notable_type] end class Default < ActiveRecord::Base acts_as_nested_set set_table_name 'categories' end class ScopedCategory < ActiveRecord::Base acts_as_nested_set :scope => :organization set_table_name 'categories' end class RenamedColumns < ActiveRecord::Base acts_as_nested_set :parent_column => 'mother_id', :left_column => 'red', :right_column => 'black', :depth_column => 'level' end class NestedSetTest < ActiveSupport::TestCase def test_left_column_default assert_equal 'lft', Default.acts_as_nested_set_options[:left_column] end def test_right_column_default assert_equal 'rgt', Default.acts_as_nested_set_options[:right_column] end def test_parent_column_default assert_equal 'parent_id', Default.acts_as_nested_set_options[:parent_column] end def test_depth_column_default assert_equal 'depth', Default.acts_as_nested_set_options[:depth_column] end def test_scope_default assert_nil Default.acts_as_nested_set_options[:scope] end def test_left_column_default assert_equal 'lft', Default.left_column_name assert_equal 'lft', Default.new.left_column_name assert_equal 'red', RenamedColumns.left_column_name assert_equal 'red', RenamedColumns.new.left_column_name end def test_right_column_name assert_equal 'rgt', Default.right_column_name assert_equal 'rgt', Default.new.right_column_name assert_equal 'black', RenamedColumns.right_column_name assert_equal 'black', RenamedColumns.new.right_column_name end def test_parent_column_name assert_equal 'parent_id', Default.parent_column_name assert_equal 'parent_id', Default.new.parent_column_name assert_equal 'mother_id', RenamedColumns.parent_column_name assert_equal 'mother_id', RenamedColumns.new.parent_column_name end def test_depth_column_name assert_equal 'depth', Default.depth_column_name assert_equal 'depth', Default.new.depth_column_name assert_equal 'level', RenamedColumns.depth_column_name assert_equal 'level', RenamedColumns.new.depth_column_name end def test_creation_with_altered_column_names assert_nothing_raised do RenamedColumns.create!() end end def test_quoted_left_column_name quoted = Default.connection.quote_column_name('lft') assert_equal quoted, Default.quoted_left_column_name assert_equal quoted, Default.new.quoted_left_column_name end def test_quoted_right_column_name quoted = Default.connection.quote_column_name('rgt') assert_equal quoted, Default.quoted_right_column_name assert_equal quoted, Default.new.quoted_right_column_name end def test_quoted_depth_column_name quoted = Default.connection.quote_column_name('depth') assert_equal quoted, Default.quoted_depth_column_name assert_equal quoted, Default.new.quoted_depth_column_name end def test_left_column_protected_from_assignment assert_raises(ActiveRecord::ActiveRecordError) { Category.new.lft = 1 } end def test_right_column_protected_from_assignment assert_raises(ActiveRecord::ActiveRecordError) { Category.new.rgt = 1 } end def test_colums_protected_on_initialize c = Category.new(:lft => 1, :rgt => 2) assert_nil c.lft assert_nil c.rgt end def test_scoped_appends_id assert_equal :organization_id, ScopedCategory.acts_as_nested_set_options[:scope] end def test_roots_class_method assert_equal Category.find_all_by_parent_id(nil), Category.roots end def test_root_class_method assert_equal categories(:top_level), Category.root end def test_root assert_equal categories(:top_level), categories(:child_3).root end def test_root? assert categories(:top_level).root? assert categories(:top_level_2).root? end def test_leaves_class_method assert_equal Category.find(:all, :conditions => "#{Category.right_column_name} - #{Category.left_column_name} = 1"), Category.leaves assert_equal Category.leaves.count, 4 assert (Category.leaves.include? categories(:child_1)) assert (Category.leaves.include? categories(:child_2_1)) assert (Category.leaves.include? categories(:child_3)) assert (Category.leaves.include? categories(:top_level_2)) end def test_leaf assert categories(:child_1).leaf? assert categories(:child_2_1).leaf? assert categories(:child_3).leaf? assert categories(:top_level_2).leaf? assert !categories(:top_level).leaf? assert !categories(:child_2).leaf? assert !Category.new.leaf? end def test_parent assert_equal categories(:child_2), categories(:child_2_1).parent end def test_self_and_ancestors child = categories(:child_2_1) self_and_ancestors = [categories(:top_level), categories(:child_2), child] assert_equal self_and_ancestors, child.self_and_ancestors end def test_ancestors child = categories(:child_2_1) ancestors = [categories(:top_level), categories(:child_2)] assert_equal ancestors, child.ancestors end def test_self_and_siblings child = categories(:child_2) self_and_siblings = [categories(:child_1), child, categories(:child_3)] assert_equal self_and_siblings, child.self_and_siblings assert_nothing_raised do tops = [categories(:top_level), categories(:top_level_2)] assert_equal tops, categories(:top_level).self_and_siblings end end def test_siblings child = categories(:child_2) siblings = [categories(:child_1), categories(:child_3)] assert_equal siblings, child.siblings end def test_leaves leaves = [categories(:child_1), categories(:child_2_1), categories(:child_3)] assert_equal categories(:top_level).leaves, leaves end def test_level assert_equal 0, categories(:top_level).level assert_equal 1, categories(:child_1).level assert_equal 2, categories(:child_2_1).level end def test_depth assert_equal 0, categories(:top_level).depth assert_equal 1, categories(:child_1).depth assert_equal 2, categories(:child_2_1).depth end def test_depth_after_move categories(:child_2).move_to_root assert_equal 0, categories(:child_2).depth assert_equal 1, categories(:child_2_1).depth categories(:child_2).move_to_child_of(categories(:top_level_2)) assert_equal 1, categories(:child_2).depth assert_equal 2, categories(:child_2_1).reload.depth end def test_has_children? assert categories(:child_2_1).children.empty? assert !categories(:child_2).children.empty? assert !categories(:top_level).children.empty? end def test_self_and_descendents parent = categories(:top_level) self_and_descendants = [parent, categories(:child_1), categories(:child_2), categories(:child_2_1), categories(:child_3)] assert_equal self_and_descendants, parent.self_and_descendants assert_equal self_and_descendants, parent.self_and_descendants.count end def test_descendents lawyers = Category.create!(:name => "lawyers") us = Category.create!(:name => "United States") us.move_to_child_of(lawyers) patent = Category.create!(:name => "Patent Law") patent.move_to_child_of(us) lawyers.reload assert_equal 1, lawyers.children.size assert_equal 1, us.children.size assert_equal 2, lawyers.descendants.size end def test_self_and_descendents parent = categories(:top_level) descendants = [categories(:child_1), categories(:child_2), categories(:child_2_1), categories(:child_3)] assert_equal descendants, parent.descendants end def test_children category = categories(:top_level) category.children.each {|c| assert_equal category.id, c.parent_id } end def test_order_of_children categories(:child_2).move_left assert_equal categories(:child_2), categories(:top_level).children[0] assert_equal categories(:child_1), categories(:top_level).children[1] assert_equal categories(:child_3), categories(:top_level).children[2] end def test_is_or_is_ancestor_of? assert categories(:top_level).is_or_is_ancestor_of?(categories(:child_1)) assert categories(:top_level).is_or_is_ancestor_of?(categories(:child_2_1)) assert categories(:child_2).is_or_is_ancestor_of?(categories(:child_2_1)) assert !categories(:child_2_1).is_or_is_ancestor_of?(categories(:child_2)) assert !categories(:child_1).is_or_is_ancestor_of?(categories(:child_2)) assert categories(:child_1).is_or_is_ancestor_of?(categories(:child_1)) end def test_is_ancestor_of? assert categories(:top_level).is_ancestor_of?(categories(:child_1)) assert categories(:top_level).is_ancestor_of?(categories(:child_2_1)) assert categories(:child_2).is_ancestor_of?(categories(:child_2_1)) assert !categories(:child_2_1).is_ancestor_of?(categories(:child_2)) assert !categories(:child_1).is_ancestor_of?(categories(:child_2)) assert !categories(:child_1).is_ancestor_of?(categories(:child_1)) end def test_is_or_is_ancestor_of_with_scope root = ScopedCategory.root child = root.children.first assert root.is_or_is_ancestor_of?(child) child.update_attribute :organization_id, 'different' assert !root.is_or_is_ancestor_of?(child) end def test_is_or_is_descendant_of? assert categories(:child_1).is_or_is_descendant_of?(categories(:top_level)) assert categories(:child_2_1).is_or_is_descendant_of?(categories(:top_level)) assert categories(:child_2_1).is_or_is_descendant_of?(categories(:child_2)) assert !categories(:child_2).is_or_is_descendant_of?(categories(:child_2_1)) assert !categories(:child_2).is_or_is_descendant_of?(categories(:child_1)) assert categories(:child_1).is_or_is_descendant_of?(categories(:child_1)) end def test_is_descendant_of? assert categories(:child_1).is_descendant_of?(categories(:top_level)) assert categories(:child_2_1).is_descendant_of?(categories(:top_level)) assert categories(:child_2_1).is_descendant_of?(categories(:child_2)) assert !categories(:child_2).is_descendant_of?(categories(:child_2_1)) assert !categories(:child_2).is_descendant_of?(categories(:child_1)) assert !categories(:child_1).is_descendant_of?(categories(:child_1)) end def test_is_or_is_descendant_of_with_scope root = ScopedCategory.root child = root.children.first assert child.is_or_is_descendant_of?(root) child.update_attribute :organization_id, 'different' assert !child.is_or_is_descendant_of?(root) end def test_same_scope? root = ScopedCategory.root child = root.children.first assert child.same_scope?(root) child.update_attribute :organization_id, 'different' assert !child.same_scope?(root) end def test_left_sibling assert_equal categories(:child_1), categories(:child_2).left_sibling assert_equal categories(:child_2), categories(:child_3).left_sibling end def test_left_sibling_of_root assert_nil categories(:top_level).left_sibling end def test_left_sibling_without_siblings assert_nil categories(:child_2_1).left_sibling end def test_left_sibling_of_leftmost_node assert_nil categories(:child_1).left_sibling end def test_right_sibling assert_equal categories(:child_3), categories(:child_2).right_sibling assert_equal categories(:child_2), categories(:child_1).right_sibling end def test_right_sibling_of_root assert_equal categories(:top_level_2), categories(:top_level).right_sibling assert_nil categories(:top_level_2).right_sibling end def test_right_sibling_without_siblings assert_nil categories(:child_2_1).right_sibling end def test_right_sibling_of_rightmost_node assert_nil categories(:child_3).right_sibling end def test_move_left categories(:child_2).move_left assert_nil categories(:child_2).left_sibling assert_equal categories(:child_1), categories(:child_2).right_sibling assert Category.valid? end def test_move_right categories(:child_2).move_right assert_nil categories(:child_2).right_sibling assert_equal categories(:child_3), categories(:child_2).left_sibling assert Category.valid? end def test_move_to_left_of categories(:child_3).move_to_left_of(categories(:child_1)) assert_nil categories(:child_3).left_sibling assert_equal categories(:child_1), categories(:child_3).right_sibling assert Category.valid? end def test_move_to_right_of categories(:child_1).move_to_right_of(categories(:child_3)) assert_nil categories(:child_1).right_sibling assert_equal categories(:child_3), categories(:child_1).left_sibling assert Category.valid? end def test_move_to_root categories(:child_2).move_to_root assert_nil categories(:child_2).parent assert_equal 0, categories(:child_2).level assert_equal 1, categories(:child_2_1).level assert_equal 1, categories(:child_2).left assert_equal 4, categories(:child_2).right assert Category.valid? end def test_move_to_child_of categories(:child_1).move_to_child_of(categories(:child_3)) assert_equal categories(:child_3).id, categories(:child_1).parent_id assert Category.valid? end def test_move_to_child_of_appends_to_end child = Category.create! :name => 'New Child' child.move_to_child_of categories(:top_level) assert_equal child, categories(:top_level).children.last end def test_subtree_move_to_child_of assert_equal 4, categories(:child_2).left assert_equal 7, categories(:child_2).right assert_equal 2, categories(:child_1).left assert_equal 3, categories(:child_1).right categories(:child_2).move_to_child_of(categories(:child_1)) assert Category.valid? assert_equal categories(:child_1).id, categories(:child_2).parent_id assert_equal 3, categories(:child_2).left assert_equal 6, categories(:child_2).right assert_equal 2, categories(:child_1).left assert_equal 7, categories(:child_1).right end def test_slightly_difficult_move_to_child_of assert_equal 11, categories(:top_level_2).left assert_equal 12, categories(:top_level_2).right # create a new top-level node and move single-node top-level tree inside it. new_top = Category.create(:name => 'New Top') assert_equal 13, new_top.left assert_equal 14, new_top.right categories(:top_level_2).move_to_child_of(new_top) assert Category.valid? assert_equal new_top.id, categories(:top_level_2).parent_id assert_equal 12, categories(:top_level_2).left assert_equal 13, categories(:top_level_2).right assert_equal 11, new_top.left assert_equal 14, new_top.right end def test_difficult_move_to_child_of assert_equal 1, categories(:top_level).left assert_equal 10, categories(:top_level).right assert_equal 5, categories(:child_2_1).left assert_equal 6, categories(:child_2_1).right # create a new top-level node and move an entire top-level tree inside it. new_top = Category.create(:name => 'New Top') categories(:top_level).move_to_child_of(new_top) categories(:child_2_1).reload assert Category.valid? assert_equal new_top.id, categories(:top_level).parent_id assert_equal 4, categories(:top_level).left assert_equal 13, categories(:top_level).right assert_equal 8, categories(:child_2_1).left assert_equal 9, categories(:child_2_1).right end #rebuild swaps the position of the 2 children when added using move_to_child twice onto same parent def test_move_to_child_more_than_once_per_parent_rebuild root1 = Category.create(:name => 'Root1') root2 = Category.create(:name => 'Root2') root3 = Category.create(:name => 'Root3') root2.move_to_child_of root1 root3.move_to_child_of root1 output = Category.roots.last.to_text Category.update_all('lft = null, rgt = null') Category.rebuild! assert_equal Category.roots.last.to_text, output end # doing move_to_child twice onto same parent from the furthest right first def test_move_to_child_more_than_once_per_parent_outside_in node1 = Category.create(:name => 'Node-1') node2 = Category.create(:name => 'Node-2') node3 = Category.create(:name => 'Node-3') node2.move_to_child_of node1 node3.move_to_child_of node1 output = Category.roots.last.to_text Category.update_all('lft = null, rgt = null') Category.rebuild! assert_equal Category.roots.last.to_text, output end def test_valid_with_null_lefts assert Category.valid? Category.update_all('lft = null') assert !Category.valid? end def test_valid_with_null_rights assert Category.valid? Category.update_all('rgt = null') assert !Category.valid? end def test_valid_with_missing_intermediate_node # Even though child_2_1 will still exist, it is a sign of a sloppy delete, not an invalid tree. assert Category.valid? Category.delete(categories(:child_2).id) assert Category.valid? end def test_valid_with_overlapping_and_rights assert Category.valid? categories(:top_level_2)['lft'] = 0 categories(:top_level_2).save assert !Category.valid? end def test_rebuild assert Category.valid? before_text = Category.root.to_text Category.update_all('lft = null, rgt = null') Category.rebuild! assert Category.valid? assert_equal before_text, Category.root.to_text end def test_move_possible_for_sibling assert categories(:child_2).move_possible?(categories(:child_1)) end def test_move_not_possible_to_self assert !categories(:top_level).move_possible?(categories(:top_level)) end def test_move_not_possible_to_parent categories(:top_level).descendants.each do |descendant| assert !categories(:top_level).move_possible?(descendant) assert descendant.move_possible?(categories(:top_level)) end end def test_is_or_is_ancestor_of? [:child_1, :child_2, :child_2_1, :child_3].each do |c| assert categories(:top_level).is_or_is_ancestor_of?(categories(c)) end assert !categories(:top_level).is_or_is_ancestor_of?(categories(:top_level_2)) end def test_left_and_rights_valid_with_blank_left assert Category.left_and_rights_valid? categories(:child_2)[:lft] = nil categories(:child_2).save(:validate => false) assert !Category.left_and_rights_valid? end def test_left_and_rights_valid_with_blank_right assert Category.left_and_rights_valid? categories(:child_2)[:rgt] = nil categories(:child_2).save(:validate => false) assert !Category.left_and_rights_valid? end def test_left_and_rights_valid_with_equal assert Category.left_and_rights_valid? categories(:top_level_2)[:lft] = categories(:top_level_2)[:rgt] categories(:top_level_2).save(:validate => false) assert !Category.left_and_rights_valid? end def test_left_and_rights_valid_with_left_equal_to_parent assert Category.left_and_rights_valid? categories(:child_2)[:lft] = categories(:top_level)[:lft] categories(:child_2).save(:validate => false) assert !Category.left_and_rights_valid? end def test_left_and_rights_valid_with_right_equal_to_parent assert Category.left_and_rights_valid? categories(:child_2)[:rgt] = categories(:top_level)[:rgt] categories(:child_2).save(:validate => false) assert !Category.left_and_rights_valid? end def test_moving_dirty_objects_doesnt_invalidate_tree r1 = Category.create r2 = Category.create r3 = Category.create r4 = Category.create nodes = [r1, r2, r3, r4] r2.move_to_child_of(r1) assert Category.valid? r3.move_to_child_of(r1) assert Category.valid? r4.move_to_child_of(r2) assert Category.valid? end def test_multi_scoped_no_duplicates_for_columns? assert_nothing_raised do Note.no_duplicates_for_columns? end end def test_multi_scoped_all_roots_valid? assert_nothing_raised do Note.all_roots_valid? end end def test_multi_scoped note1 = Note.create!(:body => "A", :notable_id => 2, :notable_type => 'Category') note2 = Note.create!(:body => "B", :notable_id => 2, :notable_type => 'Category') note3 = Note.create!(:body => "C", :notable_id => 2, :notable_type => 'Default') assert_equal [note1, note2], note1.self_and_siblings assert_equal [note3], note3.self_and_siblings end def test_multi_scoped_rebuild root = Note.create!(:body => "A", :notable_id => 3, :notable_type => 'Category') child1 = Note.create!(:body => "B", :notable_id => 3, :notable_type => 'Category') child2 = Note.create!(:body => "C", :notable_id => 3, :notable_type => 'Category') child1.move_to_child_of root child2.move_to_child_of root Note.update_all('lft = null, rgt = null') Note.rebuild! assert_equal Note.roots.find_by_body('A'), root assert_equal [child1, child2], Note.roots.find_by_body('A').children end def test_same_scope_with_multi_scopes assert_nothing_raised do notes(:scope1).same_scope?(notes(:child_1)) end assert notes(:scope1).same_scope?(notes(:child_1)) assert notes(:child_1).same_scope?(notes(:scope1)) assert !notes(:scope1).same_scope?(notes(:scope2)) end def test_quoting_of_multi_scope_column_names assert_equal ["\"notable_id\"", "\"notable_type\""], Note.quoted_scope_column_names end def test_equal_in_same_scope assert_equal notes(:scope1), notes(:scope1) assert_not_equal notes(:scope1), notes(:child_1) end def test_equal_in_different_scopes assert_not_equal notes(:scope1), notes(:scope2) end def test_delete_does_not_invalidate Category.acts_as_nested_set_options[:dependent] = :delete categories(:child_2).destroy assert Category.valid? end def test_destroy_does_not_invalidate Category.acts_as_nested_set_options[:dependent] = :destroy categories(:child_2).destroy assert Category.valid? end def test_destroy_multiple_times_does_not_invalidate Category.acts_as_nested_set_options[:dependent] = :destroy categories(:child_2).destroy categories(:child_2).destroy assert Category.valid? end def test_assigning_parent_id_on_create category = Category.create!(:name => "Child", :parent_id => categories(:child_2).id) assert_equal categories(:child_2), category.parent assert_equal categories(:child_2).id, category.parent_id assert_not_nil category.left assert_not_nil category.right assert Category.valid? end def test_assigning_parent_on_create category = Category.create!(:name => "Child", :parent => categories(:child_2)) assert_equal categories(:child_2), category.parent assert_equal categories(:child_2).id, category.parent_id assert_not_nil category.left assert_not_nil category.right assert Category.valid? end def test_assigning_parent_id_to_nil_on_create category = Category.create!(:name => "New Root", :parent_id => nil) assert_nil category.parent assert_nil category.parent_id assert_not_nil category.left assert_not_nil category.right assert Category.valid? end def test_assigning_parent_id_on_update category = categories(:child_2_1) category.parent_id = categories(:child_3).id category.save assert_equal categories(:child_3), category.parent assert_equal categories(:child_3).id, category.parent_id assert Category.valid? end def test_assigning_parent_on_update category = categories(:child_2_1) category.parent = categories(:child_3) category.save assert_equal categories(:child_3), category.parent assert_equal categories(:child_3).id, category.parent_id assert Category.valid? end def test_assigning_parent_id_to_nil_on_update category = categories(:child_2_1) category.parent_id = nil category.save assert_nil category.parent assert_nil category.parent_id assert Category.valid? end def test_creating_child_from_parent category = categories(:child_2).children.create!(:name => "Child") assert_equal categories(:child_2), category.parent assert_equal categories(:child_2).id, category.parent_id assert_not_nil category.left assert_not_nil category.right assert Category.valid? end def check_structure(entries, structure) structure = structure.dup Category.each_with_level(entries) do |category, level| expected_level, expected_name = structure.shift assert_equal expected_name, category.name, "wrong category" assert_equal expected_level, level, "wrong level for #{category.name}" end end def check_scoped_structure(entries, structure) structure = structure.dup entries.each_with_level do |category, level| expected_level, expected_name = structure.shift assert_equal expected_name, category.name, "wrong category" assert_equal expected_level, level, "wrong level for #{category.name}" end end def test_each_with_level levels = [ [0, "Top Level"], [1, "Child 1"], [1, "Child 2"], [2, "Child 2.1"], [1, "Child 3" ]] check_structure(Category.root.self_and_descendants, levels) check_scoped_structure(Category.root.self_and_descendants, levels) # test some deeper structures category = Category.find_by_name("Child 1") c1 = Category.new(:name => "Child 1.1") c2 = Category.new(:name => "Child 1.1.1") c3 = Category.new(:name => "Child 1.1.1.1") c4 = Category.new(:name => "Child 1.2") [c1, c2, c3, c4].each(&:save!) c1.move_to_child_of(category) c2.move_to_child_of(c1) c3.move_to_child_of(c2) c4.move_to_child_of(category) levels = [ [0, "Top Level"], [1, "Child 1"], [2, "Child 1.1"], [3, "Child 1.1.1"], [4, "Child 1.1.1.1"], [2, "Child 1.2"], [1, "Child 2"], [2, "Child 2.1"], [1, "Child 3" ]] check_scoped_structure(Category.root.self_and_descendants, levels) end def test_model_with_attr_accessible model = Class.new(ActiveRecord::Base) model.set_table_name 'categories' model.attr_accessible :name assert_nothing_raised do model.acts_as_nested_set model.new(:name => 'foo') end end def test_before_move_callback $called = false Category.before_move { |r| $called = true } categories(:child_2).move_to_root assert $called ensure Category.class_eval { reset_callbacks :move } end def test_before_move_callback_returning_false_stops_move Category.before_move { |r| false } assert !categories(:child_3).move_to_root assert !categories(:child_3).root? ensure Category.class_eval { reset_callbacks :move } end # NOTE this feature is hard to implement given current callbacks # architecture. Since node is moved in an after_save hook, # we can't stop moving by before filter. The only thing we can do # is raise an exception preventing Model#save to commit transaction. #def test_before_move_callback_returning_false_halts_save #Category.before_move { |r| false } #categories(:child_3).parent_id = nil #assert !categories(:child_3).save #ensure #Category.class_eval { reset_callbacks :move } #end def test_calls_after_move_when_moving $called = false Category.after_move { $called = true } categories(:child_3).parent = categories(:child_2) assert categories(:child_3).save assert $called ensure Category.class_eval { reset_callbacks :move } end # helper to turn arranged hash to levels array def hash_to_array hash, level = 0 array = [] hash.each do |key, value| array.push [level, "#{key}"] array += hash_to_array(value, level.next) end array end def test_arrangement levels = [ [0, "Top Level"], [1, "Child 1"], [1, "Child 2"], [2, "Child 2.1"], [1, "Child 3"], [0, "Top Level 2"]] assert_equal hash_to_array(Category.arrange), levels # some deeper structure category = Category.find_by_name("Child 1") c1 = Category.new(:name => "Child 1.1") c2 = Category.new(:name => "Child 1.1.1") c3 = Category.new(:name => "Child 1.1.1.1") c4 = Category.new(:name => "Child 1.2") [c1, c2, c3, c4].each(&:save!) c1.move_to_child_of(category) c2.move_to_child_of(c1) c3.move_to_child_of(c2) c4.move_to_child_of(category) levels = [ [0, "Top Level"], [1, "Child 1"], [2, "Child 1.1"], [3, "Child 1.1.1"], [4, "Child 1.1.1.1"], [2, "Child 1.2"], [1, "Child 2"], [2, "Child 2.1"], [1, "Child 3" ], [0, "Top Level 2"]] assert_equal hash_to_array(Category.arrange), levels end end