function test_order_by_unknown_field_is_ignored() { $dt = new DataTable("http://example.org/store"); $dt->map('http://example.org/name', 'name'); $dt->select('name'); $dt->order_by('foo'); $this->assertEquals("select ?_uri ?name where {?_uri <http://example.org/name> ?name. }", $dt->get_sparql()); }