set(EditableTextField::class, 'autocomplete_options', ['foo' => 'foo']); $field = new EditableTextField; $result = $field->getCMSFields(); $autocompleteField = $result->fieldByName('Root.Main.Autocomplete'); $this->assertInstanceOf(DropdownField::class, $autocompleteField); $this->assertEquals(['foo' => 'foo'], $autocompleteField->getSource()); } }