Test adding a tag and metadata to the Entity query object.
The tags and metadata should propogate to the SQL query object.
function testMetaData() {
$query = entity_query('test_entity');
$query
->addTag('efq_metadata_test')
->addMetaData('foo', 'bar')
->execute();
global $efq_test_metadata;
$this
->assertEqual($efq_test_metadata, 'bar', 'Tag and metadata propogated to the SQL query object.');
}