test with renderGutter.tsx

// Props of the <DiffView> component:
     
   type DiffProps = {
    children: (hunks: HunkInfo[]) => ReactNode;
    className?: string;
    diffType: string;
    hunks: Hunks;
    tokens?: Tokens;
    viewType: ViewType;
    gutterType?: 'default' | 'anchor' | 'none';
    generateAnchorID?: (change: ChangeInfo) => string;
    selectedChanges?: string[];
    widgets?: WidgetMap;
    renderGutter?: RenderGutter;
  };

  
// Test code
const root = renderWithLinterProvider({ diff });
const { renderGutter } = root.find(Diff).props();

const gutter = shallow(renderGutter());