JamesMoss\Flywheel\Document::setId PHP Method

    public function setId($id)
    {
        $id = (string) $id;
        if (!isset($this->__flywheelInitialId)) {
            $this->__flywheelInitialId = $id;
        }
        $this->__flywheelDocId = $id;
        return $id;
    }

 public function testGettingInitialId()
 {
     $doc = new Document(array('mike' => 'snow'));
     $doc->setId('albums');
     $this->assertEquals('albums', $doc->getInitialId());
     $doc->setId('singles');
     $this->assertEquals('albums', $doc->getInitialId());
 }