I am trying to create `SelectColumn.test.js` similar to `Summary.test.js`

<https://gitlab.com/sosy-lab/software/benchexec/-/blob/SelectColumn.test/benchexec/tablegenerator/react-table/src/tests/SelectColumn.test.js>

But unfortunately not successful, I tried all solutions from code forums. But seems I am doing something wrong.

> 
> Result: failed
> 
> 
> Expected result should be: passed
> 
> 
> 

Error:

> 
> react-modal: No elements were found for selector #root.
> 
> 
> 

```
      180 | 
      181 |   render() {
    > 182 |     ReactModal.setAppElement("#root");
          |                ^
      183 |     return (
      184 |       <ReactModal
      185 |         className="overlay"

```

**Edited on 01.03.2020:**

I added `<div id="root">` which fixed error:

> 
> react-modal: No elements were found for selector #root.
> 
> 
> 

but now new error is showing:

> 
> TypeError: parentInstance.children.indexOf is not a function
> 
> 
> 

in code:

```
      81 |           .create(<Overview data={data} />)
      82 |           .getInstance();
    > 83 |         const component = renderer.create(component_func(overview));
         |                                    ^
      84 | 
      85 |         expect(component).toMatchSnapshot();
      86 |       });

```

I tried to move `ReactModal.setAppElement` to `componentDidMount` but it seems not to be the solution.

**Edited on 04.03.2020:**

Now I changed my code so it tests from the main component from `App.js` which works great, but I want to test just the child component `SelectColumn`. I tried with `shallow` and `find` but the snapshot is always `exports[...] = null;`

```
import React from "react";
import SelectColumn from "../App.js";
import { test_snapshot_of } from "./utils.js";
import Enzyme, { shallow } from "enzyme";
import Adapter from "enzyme-adapter-react-16";

Enzyme.configure({ adapter: new Adapter() });

// mock uniqid to have consistent names
// https://stackoverflow.com/a/44538270/396730
jest.mock("uniqid", () => i => i + "uniqid");

const wrapper = shallow(<SelectColumn />);
const rootElement = wrapper.find("#root");
test_snapshot_of("Render SelectColumn", overview => rootElement);

```