.name         @node_group_a.save          @node_group_a.should_not be_valid         @node_group_a.errors.full_messages.should include("Validation failed: Creating a dependency from group 'A' to itself creates a cycle")         @node_group_a.node_groups.should be_empty       end        it "should not allow a cycle to be formed" do         @node_group_b.node_groups << @node_group_a         @node_group_a.assigned_node_group_names = @node_group_