remove('EditableTextField', 'autocomplete_options'); Config::inst()->update('EditableTextField', 'autocomplete_options', array('foo' => 'foo')); $field = new EditableTextField; $result = $field->getCMSFields(); $autocompleteField = $result->fieldByName('Root.Main.Autocomplete'); $this->assertInstanceOf('DropdownField', $autocompleteField); $this->assertEquals(array('foo' => 'foo'), $autocompleteField->getSource()); } }