/**
  * @covers ::isValueEmpty
  */
 public function testIsValueEmpty()
 {
     $key = ['foo', 'bar'];
     $is_empty = TRUE;
     $this->decoratedFormState->isValueEmpty($key)->willReturn($is_empty)->shouldBeCalled();
     $this->assertSame($is_empty, $this->formStateDecoratorBase->isValueEmpty($key));
 }