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**Do you want to request a *feature* or report a *bug*?** Bug, I guess

**What is the current behavior?** 


```
  console.error node_modules/fbjs/lib/warning.js:33
    Warning: Detected multiple renderers concurrently rendering the same context provider. This is currently unsupported.
```

Steps to reproduce the behavior:
1. `git clone https://github.com/stereobooster/react-context-issue`
2. `cd react-context-issue`
3. `yarn`
4. `yarn test`

**What is the expected behavior?** no warning

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?** React 16.4. Browser not affected, because error is in node.js

Open this because of https://github.com/facebook/react/pull/13127#issuecomment-402527012

Issue happens because of Enzyme (https://github.com/airbnb/enzyme/issues/1693), code is unreleased, so I copy-pasted it from master. 

I'm looking for advice or some clue on how to fix this, so I would be able to create PR in Enzyme repo (or in React repo if this is the case). Thank you.


<Circle radius={10} stroke="green" strokeWidth={3} fill="blue" />,
    );
    expect(circle.toJSON()).toMatchSnapshot();
  });
  it('should warn if radius is missing on a Circle component', () => {
    expect(() =>
      ReactTestRenderer.create(
        <Circle stroke="green" strokeWidth={3} fill="blue" />,
      ),
    ).toWarnDev(
      'Warning: Failed prop type: The prop `radius` is marked as required in `Circle`, ' +
        'but its value is `undefined`.' +
        '\n    in Circle (at **)',
    );
  });
  it('should generate a <Shape> with props for drawing the Rectangle', () => {
    const rectangle = ReactTestRenderer.create(
      <Rectangle width={50} height={50} stroke="green" fill="blue" />,
    );
    expect(rectangle.toJSON()).toMatchSnapshot();
  });
  it('should warn if width/height is missing on a Rectangle component', () => {
    expect(() =>
      ReactTestRenderer.create(<Rectangle stroke="green" fill="blue" />),
    ).toWarnDev([
      'Warning: Failed prop type: The prop `width` is marked as required in `Rectangle`, ' +
        'but its value is `undefined`.' +
        '\n    in Rectangle (at **)',
      'Warning: Failed prop type: The prop `height` is marked as required in `Rectangle`, ' +
        'but its value is `undefined`.' +