public function testInternalWithCombinedPkKeys()
{
$data = array(array('client_id' => 1, 'invoice_id' => 4, 'title' => 'Payment1'), array('client_id' => 2, 'invoice_id' => 5, 'title' => 'Payment2'), array('client_id' => 3, 'invoice_id' => 6, 'title' => 'Payment3'));
$payments = new MockMultiKeyRecordSet(array('data' => $data, 'model' => $this->_model2));
$expected = array(array('client_id' => 1, 'invoice_id' => 4), array('client_id' => 2, 'invoice_id' => 5), array('client_id' => 3, 'invoice_id' => 6));
$this->assertEqual($expected, $payments->keys());
}