import { adjustDate } from './adjust-date' ; describe ( 'Adjust a given date by a given change in duration.' , ( ) => { const date = new Date ( '2021-09-20T21:06:51.517Z' ) ; it ( 'returns undefined when the adjustment isnt in a supported format' , ( ) => { expect ( adjustDate ( date , '-ms1' ) ) . toBe ( undefined ) ; } ) ; it ( 'subtracts a year from the date' , ( ) => { const adjustedDate = new Date ( '2020-09-20T21:06:51.517Z' ) ; expect ( adjustDate ( date , '-1.0y' ) ) . toStrictEqual ( adjustedDate ) ; } ) ; it ( 'subtracts a month from the date' , ( ) => { const adjustedDate = new Date ( '2021-08-20T21:06:51.517Z' ) ; expect ( adjustDate ( date , '-1.0mo' ) ) . toStrictEqual ( adjustedDate ) ; } ) ; it ( 'subtracts a week from the date' , ( ) => { const adjustedDate = new Date ( '2021-09-13T21:06:51.517Z' ) ; expect ( adjustDate ( date , '-1.0weeks' ) ) . toStrictEqual ( adjustedDate ) ; } ) ; it ( 'subtracts a day from the date' , ( ) => { const adjustedDate = new Date ( '2021-09-19T21:06:51.517Z' ) ; expect ( adjustDate ( date , '-1.0' ) ) . toStrictEqual ( adjustedDate ) ; } ) ; it ( 'subtracts an hour from the date' , ( ) => { const adjustedDate = new Date ( '2021-09-20T20:06:51.517Z' ) ; expect ( adjustDate ( date , '-1.0h' ) ) . toStrictEqual ( adjustedDate ) ; } ) ; it ( 'subtracts a minute from the date' , ( ) => { const adjustedDate = new Date ( '2021-09-20T21:05:51.517Z' ) ; expect ( adjustDate ( date , '-1.0minutes' ) ) . toStrictEqual ( adjustedDate ) ; } ) ; it ( 'subtracts a second from the date' , ( ) => { const adjustedDate = new Date ( '2021-09-20T21:06:50.517Z' ) ; expect ( adjustDate ( date , '-1.0secs' ) ) . toStrictEqual ( adjustedDate ) ; } ) ; it ( 'subtracts a millisecond from the date' , ( ) => { const adjustedDate = new Date ( '2021-09-20T21:06:51.516Z' ) ; expect ( adjustDate ( date , '-1.0ms' ) ) . toStrictEqual ( adjustedDate ) ; } ) ; } ) ;