Box\Spout\Writer\Style\Style::getId PHP Method

    public function getId()
    {
        return $this->id;
    }

 /**
  * @return void
  */
 public function testRegisterStyleShouldUpdateId()
 {
     $style1 = (new StyleBuilder())->setFontBold()->build();
     $style2 = (new StyleBuilder())->setFontUnderline()->build();
     $this->assertEquals(0, $this->defaultStyle->getId(), 'Default style ID should be 0');
     $this->assertNull($style1->getId());
     $this->assertNull($style2->getId());
     $styleHelper = new StyleHelper($this->defaultStyle);
     $registeredStyle1 = $styleHelper->registerStyle($style1);
     $registeredStyle2 = $styleHelper->registerStyle($style2);
     $this->assertEquals(1, $registeredStyle1->getId());
     $this->assertEquals(2, $registeredStyle2->getId());
 }