public function testClearAllHeaders()
{
$this->_response->setRawHeader('HTTP/1.0 404 Not Found');
$this->_response->setHeader('Content-Type', 'text/xml');
$headers = $this->_response->getHeaders();
$this->assertFalse(empty($headers));
$headers = $this->_response->getRawHeaders();
$this->assertFalse(empty($headers));
$this->_response->clearAllHeaders();
$headers = $this->_response->getHeaders();
$this->assertTrue(empty($headers));
$headers = $this->_response->getRawHeaders();
$this->assertTrue(empty($headers));
}