/**
  * @covers ::valueCallback
  *
  * @dataProvider providerTestValueCallback
  */
 public function testValueCallback($expected, $input) {
   $element = [];
   $form_state = $this->prophesize(FormStateInterface::class)->reveal();
   $this->assertSame($expected, MachineName::valueCallback($element, $input, $form_state));
 }