How to write unit test case?

Like 
  <HexColorPicker
                    data-testid='colorPicker'
                    color={color}
                    onChange={onChange}
                  />
 const colorPicker = screen.getByTestId('colorPicker');
    fireEvent.change(colorPicker, { target: { value: '#ff0000' } });
it's not working any alternative solution change color value?