public function testSetDataSources()
 {
     $ds1 = new HTML_QuickForm2_DataSource_Array(array('key' => 'value'));
     $ds2 = new HTML_QuickForm2_DataSource_Array(array('another key' => 'foo'));
     $form = new HTML_QuickForm2('dstest');
     $this->assertEquals(0, count($form->getDataSources()));
     $form->addDataSource($ds2);
     $this->assertEquals(1, count($form->getDataSources()));
     $form->setDataSources(array($ds1, $ds2));
     $this->assertEquals(2, count($form->getDataSources()));
     try {
         $form->setDataSources(array($ds1, 'bogus', $ds2));
     } catch (HTML_QuickForm2_InvalidArgumentException $e) {
         return;
     }
     $this->fail('Expected HTML_QuickForm2_InvalidArgumentException was not thrown');
 }