Enzyme fails to return text or html when shallow rendering

[Sawtaytoes]

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Description

What you are reporting:
When shallow rendering in enzyme, text and html functions return null strings.

I tried a few things when reproducing. First, this works fine in v3. Merely upgrading to v4 without changing any other code is can cause this issue. I tried removing all React Hot Loader code and nothing changed.

If I do a mount instead of shallow render, it works fine which makes me think something's getting rendered in between.

Expected behavior

What you think should happen:
wrapper.text() should have the value hi and any other text in the component.

Actual behavior

What actually happens:
wrapper.text() returns a null string ''.

Environment

React Hot Loader version: 4.0.0

Run these commands in the project folder and fill in their results:

1. node -v: v8.9.4
2. yarn-v: 1.3.2

Then, specify:

1. Operating system: Windows 10 64-bit
2. Browser and version: Chrome 66.0.3359.33 beta 64-bit

Reproducible Demo

.babelrc

{
  "plugins": [
    "add-react-displayname",
    "extract-hoc/babel",
    "react-hot-loader/babel",
    "transform-class-properties",
    "transform-object-rest-spread",
    "transform-runtime",
  ],
  "presets": [
    [
      "env", {
        "modules": false,
      }
    ],
    "react",
  ],
}

entrypoint.js

import Adapter from 'enzyme-adapter-react-16'
import React from 'react'
import { configure } from 'enzyme'
import { shallow } from 'enzyme'

// Setup Enzyme for React 16
configure({ adapter: new Adapter() })

const TestComponent = () => <div>hi</div>
const wrapper = shallow(<TestComponent />)

console.log(
  'Should be true:',
  wrapper.text() === 'hi'
)

[theKashey]

Quite strange - outside of webpack dev env, ie without module.hot enabled, RHL should not affect anything. And not affecting by fact.

[Sawtaytoes]

That would be because I have hot: true. I'm running unit tests in the browser and React is showing information about the tests, parsing TAP output messages.

[theKashey]

Now I see.
To be honest - we never tested RHL in such environment. Even more - we had an issue then RHL just blow up Jest, I mean - completely.
I'll try to investigate that is happening and how we could mitigate the problem, but now I can't give you any advise, sorry.

[Sawtaytoes]

I understand.

I found a workaround for my issues with v3, so I at least have a working solution for now.

v4's hot allows hot reloading React components in legacy applications such as AngularJS which I do have to deal with.

The v4 workaround is doing a full mount instead of shallow. This had the unintended side effect of mounting components that use Redux or React-Router down the chain. Unless I have an explicit need, I don't mock Redux when testing.

[theKashey]

Theoretically - is RHL working ok with mount, it shall work with shallow. Theoretically.