import * as React from "react" ; import { render } from "reakit-test-utils" ; import { useForkRef } from "../useForkRef" ; test ( "useForkRef" , ( ) => { expect . assertions ( 2 ) ; const externalRef = React . createRef < HTMLElement > ( ) ; const Component = React . forwardRef ( ( props , ref ) => { const internalRef = React . useRef < HTMLElement > ( null ) ; React . useEffect ( ( ) => { expect ( internalRef . current ) . toBeInTheDocument ( ) ; } , [ ] ) ; return < div ref = { useForkRef ( internalRef , ref ) } { ... props } />; } ) ; render ( < Component ref = { externalRef } / > ) ; expect ( externalRef . current ) . toBeInTheDocument ( ) ; } ) ;