How i can simply make unit testing for the value of input type file :

<input required type="file" class="form-control blue-border" accept=".jpg, .jpeg, .png" data-testid="file" /> 

I tryed

descripe('ex....',()=>{
     test('ex.....',()=>{
     const file=screen.getByTestId('file')
     expect(file.value='myfile.png').toContain(/(\.jpg|\.jpeg|\.png)$/i)
})
})

but i have error : InvalidStateError: This input element accepts a filename, which may only be programmatically set to the empty string.