let value ; let called = 0 ; function callback ( _value ) { called ++ ; value = _value ; } export default { props : { callback } , before_test ( ) { called = 0 ; } , async test ( { assert , target , window } ) { assert . equal ( called , 1 ) ; const input = target . querySelector ( 'input' ) ; const event = new window . Event ( 'input' ) ; input . value = 'h' ; await input . dispatchEvent ( event ) ; assert . equal ( called , 2 ) ; assert . equal ( value . length , 3 ) ; assert . equal ( value [ 0 ] , 'h' ) ; assert . equal ( value [ 1 ] , '2' ) ; assert . equal ( value [ 2 ] , '3' ) ; } } ;