Symfony\Component\Form\FormBuilder::get PHP Method

    public function get($name)
    {
        if (isset($this->unresolvedChildren[$name])) {
            return $this->resolveChild($name);
        }

        if (isset($this->children[$name])) {
            return $this->children[$name];
        }

        throw new FormException(sprintf('The child with the name "%s" does not exist.', $name));
    }

 /**
  * @dataProvider getBuildPagerWithPage2Tests
  */
 public function testBuildPagerWithPage2($page, $perPage)
 {
     $this->pager->expects($this->once())->method('setMaxPerPage')->with($this->equalTo('50'))->will($this->returnValue(null));
     $this->pager->expects($this->once())->method('setPage')->with($this->equalTo('3'))->will($this->returnValue(null));
     $this->datagrid = new Datagrid($this->query, $this->columns, $this->pager, $this->formBuilder, array());
     $this->datagrid->setValue('_per_page', null, $perPage);
     $this->datagrid->setValue('_page', null, $page);
     $this->datagrid->buildPager();
     $this->assertSame(array('_per_page' => array('type' => null, 'value' => $perPage), '_page' => array('type' => null, 'value' => $page)), $this->datagrid->getValues());
     $this->assertInstanceOf('Symfony\\Component\\Form\\FormBuilder', $this->formBuilder->get('_sort_by'));
     $this->assertInstanceOf('Symfony\\Component\\Form\\FormBuilder', $this->formBuilder->get('_sort_order'));
     $this->assertInstanceOf('Symfony\\Component\\Form\\FormBuilder', $this->formBuilder->get('_page'));
     $this->assertInstanceOf('Symfony\\Component\\Form\\FormBuilder', $this->formBuilder->get('_per_page'));
 }