let callbacks = [ ] ; export default { props : { callback : ( value ) => callbacks . push ( value ) , val1 : '1' , val2 : '2' } , before_test ( ) { callbacks = [ ] ; } , async test ( { assert , component } ) { assert . equal ( callbacks . length , 2 ) ; assert . equal ( JSON . stringify ( callbacks ) , '["1","2"]' ) ; component . val1 = '3' ; assert . equal ( callbacks . length , 3 ) ; assert . equal ( JSON . stringify ( callbacks ) , '["1","2","1"]' ) ; component . val1 = '4' ; assert . equal ( callbacks . length , 4 ) ; assert . equal ( JSON . stringify ( callbacks ) , '["1","2","1","1"]' ) ; component . val2 = '5' ; assert . equal ( callbacks . length , 5 ) ; assert . equal ( JSON . stringify ( callbacks ) , '["1","2","1","1","2"]' ) ; } } ;