Shallow Render has everything wrapped in `ForwardRef` #2190

gregkerzhner · 2019-07-15T23:00:17Z

Current behavior

This is with react native. When I use shallow rendering with enzyme, all components seem to be wrapped in a forwardRef. For example, if I do this in a test

    const wrapper = shallow(
      <TestView/>
    );
    console.log(wrapper.debug())

where TestView is

export const TestView: FC<PropType> = (props: PropType) => {
  return (
    <Text>Hello World</Text>
  );
};

The resulting output is

 <ForwardRef(Text)>
    Hello World
 </ForwardRef(Text)>

The problem with this is that you cannot do wrapper.find("Text"), and instead have to do wrapper.find('ForwardRef(Text') which is a lot less clear and seems fragile.

Expected behavior

I would expect the component to be just

 <Text>
    Hello World
 </Text>

Your environment

React Native 0.59.5

API

shallow
mount
render

Version

library	version
enzyme	3.6.0
react	16.8.6
react-dom	16.0.6
react-test-renderer	16.8.6
adapter (below)

Adapter

The text was updated successfully, but these errors were encountered:

ljharb · 2019-07-16T05:59:37Z

enzyme won't work properly with react-native without a react-native adapter. Follow #1436 for that.

gregkerzhner · 2019-07-16T15:26:13Z

I am using the Adapter! mount works properly, but shallow does not. Here is my test-setup.js file

import { JSDOM } from "jsdom";

const jsdom = new JSDOM("<!doctype html><html><body></body></html>");
const { window } = jsdom;

const copyProps = (src, target) => {
  const props = Object.getOwnPropertyNames(src)
    .filter(prop => typeof target[prop] === "undefined")
    .map(prop => Object.getOwnPropertyDescriptor(src, prop));

  console.log("Props are" + props)  
  Object.defineProperties(target, props);
};

global.window = window;
global.document = window.document;
global.navigator = {
  userAgent: "node.js"
};
copyProps(window, global);

import { configure } from "enzyme";
import Adapter from "enzyme-adapter-react-16";

// Setup enzyme's react adapter
configure({ adapter: new Adapter() });

// Ignore React Web errors when using React Native
console.error = message => {
  return message;
};

ljharb · 2019-07-16T15:30:01Z

What i mean is, those adapters are for react web. There isn’t an adapter for react native atm.

gregkerzhner · 2019-07-16T15:40:59Z

Thanks for the quick response. I think what is misleading to me is the documentation then?

https://airbnb.io/enzyme/docs/guides/react-native.html

"As of v0.18, React Native uses React as a dependency rather than a forked version of the library, which means it is now possible to use enzyme's shallow with React Native components".

But if the behavior I am seeing is actually what is happening to everyone else, isn't this statement not really true? I guess you technically can use it, but it won't actually produce output thats predictable or usable.

Should I make a pull request to the documentation to say that shallow won't produce output that actually matches your component structure and is therefore not really usable?

ljharb · 2019-07-16T15:50:27Z

I suspect that at some point RN started using forwardRef in all their primitives, and that doesn’t play well with shallow.

If you shallow render your own component, it should certainly be usable - you should be using .find(Text) and not finding by display name anyways.

gregkerzhner · 2019-07-16T15:58:54Z

@ljharb thank you! You just dropped the nugget of gold that I needed. In my example above,
wrapper.find("Text") doesn't work, but wrapper.find(Text) does. I should have read the docs here better: https://airbnb.io/enzyme/docs/api/selector.html.

ljharb · 2019-07-16T16:20:07Z

It’s likely that to “fix” this, RN itself would have to explicitly set the display name on their now-forward-reffed components.

bedrich-schindler · 2020-02-28T10:32:38Z

We have similar problem when using mount. I fixed it this way:

import Enzyme from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';
import { createSerializer } from 'enzyme-to-json';

// Configure enzyme to use adapter for React
Enzyme.configure({ adapter: new Adapter() });

// Omit ForwardRef component in jest snapshot
// Bug: https://github.com/enzymejs/enzyme/issues/2190
const omitForwardRefInTree = (node) => {
  if (node.type && node.type.startsWith('ForwardRef')) {
    // ForwardRef have no child only when node is processed via `shallow` function,
    // otherwise `mount` is used.
    if (!node.children || node.children.length === 0) {
      return node;
    }

    if (node.children && node.children.length === 1) {
      return node.children[0];
    }

    return node.children;
  }

  return node;
};

// Configure jest to use json serializer for snapshot creation
expect.addSnapshotSerializer(createSerializer({
  map: omitForwardRefInTree,
  mode: 'deep',
  noKey: true,
}));

I use enzyme-to-json to render snapshots and it allows to change rendering of specific node, so I can omit it to temporarily fix the problem.

Snapshot before fix:

<ForwardRef(withForwardedRef(s))
            beforeLabel={
              <Icon
                icon="remote-connection"
                size="medium"
              />
            }
            clickHandler={[Function]}
            disabled={false}
            id="header__remoteAccessDialogButton"
            label="Remote access"
            labelVisibility="desktop"
            priority="default"
            variant="secondary"
          >
            <button
              className="Button__root__3zrxR
        Button__priorityDefault__hcWO8
        Button__sizeMedium__168V1
        Button__variantSecondary__1bYwq
        
        
        Button__withLabelHiddenMobile__3WSDW"
              disabled={false}
              id="header__remoteAccessDialogButton"
              onClick={[Function]}
              title="Remote access"
              type="button"
            >
              <span
                className="Button__beforeLabel__2TFTl"
              >
                <svgr-mock
                  height={16}
                  width={16}
                />
              </span>
              <span
                className="Button__label__3YN6e"
                id="header__remoteAccessDialogButton__label"
              >
                Remote access
              </span>
            </button>
          </ForwardRef(withForwardedRef(s))>

Snapshot after fix:

<button
            className="Button__root__3zrxR
        Button__priorityDefault__hcWO8
        Button__sizeMedium__168V1
        Button__variantSecondary__1bYwq
        
        
        Button__withLabelHiddenMobile__3WSDW"
            disabled={false}
            id="header__remoteAccessDialogButton"
            onClick={[Function]}
            title="Remote access"
            type="button"
          >
            <span
              className="Button__beforeLabel__2TFTl"
            >
              <svgr-mock
                height={16}
                width={16}
              />
            </span>
            <span
              className="Button__label__3YN6e"
              id="header__remoteAccessDialogButton__label"
            >
              Remote access
            </span>
          </button>

roni-castro · 2020-08-19T22:02:06Z

After upgrading react-native to the 0.63.2, finding an element by testing id does not work anymore, because TouchableOpacity component is wrapped by ForwardRef and it returns two nodes now instead of one.
Is there any solution to find an element by testing ID that do not return this ForwardRef or do I need to handle it (generate a logic to filter it, add wrapper around TouchabeOpacity to avoid components that have forwardRef...)?

Now it is retuning two nodes when I run: wrapper.find(`[data-ref="thumbsUp"]`) and use mount

// First node with the `data-ref = thumbsUp` 
<ForwardRef data-ref="thumbsUp" onPress={[Function: onPress]}>
     <TouchableOpacity data-ref="thumbsUp" onPress={[Function: onPress]} hostRef={{...}}>
     </TouchableOpacity> 
</ForwardRef>

// Second node with the `data-ref = thumbsUp`
<TouchableOpacity data-ref="thumbsup" onPress={[Function: onPress]} hostRef={{...}}>
</TouchableOpacity>

I had the same problem after upgrading react-native version, and I can't do find(TouchableOpacity) because it would return more than 5 different items.

roni-castro · 2020-08-21T14:10:42Z

The solution I have figured out is to add the name of component (TouchableOpacity) in the find command to be more restricted. Do something like this:

wrapper.find(`TouchableOpacity[data-ref="idOfComponent"]`)

ljharb closed this as completed Jul 16, 2019

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Shallow Render has everything wrapped in `ForwardRef` #2190

Shallow Render has everything wrapped in `ForwardRef` #2190

gregkerzhner commented Jul 15, 2019 •

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ljharb commented Jul 16, 2019

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ljharb commented Jul 16, 2019

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Shallow Render has everything wrapped in ForwardRef #2190

Shallow Render has everything wrapped in ForwardRef #2190

Comments

gregkerzhner commented Jul 15, 2019 • edited Loading

Current behavior

Expected behavior

Your environment

API

Version

Adapter

ljharb commented Jul 16, 2019

gregkerzhner commented Jul 16, 2019

ljharb commented Jul 16, 2019

gregkerzhner commented Jul 16, 2019

ljharb commented Jul 16, 2019

gregkerzhner commented Jul 16, 2019

ljharb commented Jul 16, 2019

bedrich-schindler commented Feb 28, 2020 • edited Loading

roni-castro commented Aug 19, 2020 • edited Loading

roni-castro commented Aug 21, 2020 • edited Loading

Shallow Render has everything wrapped in `ForwardRef` #2190

Shallow Render has everything wrapped in `ForwardRef` #2190

gregkerzhner commented Jul 15, 2019 •

edited

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bedrich-schindler commented Feb 28, 2020 •

edited

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roni-castro commented Aug 19, 2020 •

edited

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roni-castro commented Aug 21, 2020 •

edited

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