public function testMapField($cm)
{
$cm->mapField(array('fieldName' => 'username', 'type' => 'string'));
$cm->mapField(array('fieldName' => 'created', 'type' => 'datetime'));
$this->assertTrue(isset($cm->fieldMappings['username']));
$this->assertTrue(isset($cm->fieldMappings['created']));
$this->assertEquals(array('jsonName' => 'username', 'type' => 'string', 'fieldName' => 'username'), $cm->fieldMappings['username']);
$this->assertEquals(array('jsonName' => 'created', 'type' => 'datetime', 'fieldName' => 'created'), $cm->fieldMappings['created']);
$this->assertEquals(array('_id' => 'id', 'username' => 'username', 'created' => 'created'), $cm->jsonNames);
return $cm;
}