Shallow `contain` fails

The documentation for contain states that I can assert a shallow wrapper contains a node, but this SSCE fails:

import React, {Component} from 'react';

function ChildComponent() {
  return <div className="child" />;
}

class MyComponent extends Component {
  render() {
    return (
      <div>
        <ChildComponent />
      </div>
    );
  }
}

describe('My Component', function () {
  it('renders the child', () => {
    const wrapper = shallow(<MyComponent />);
    expect(wrapper).to.contain(<ChildComponent />);
  });

  it('finds the child', () => {
    const wrapper = shallow(<MyComponent />);
    expect(wrapper.find(ChildComponent)).to.have.length(1);
  });
});

it('renders the child') throws the following error:

AssertionError: expected { Object (root, unrendered, ...) } to have a property '$$typeof'

but it('finds the child') passes.

(Note that I have expect and shallow available as globals in my Mocha test env.)

Are the docs wrong or am I using this method incorrectly?

[ayrton]

The problem is that you didn’t set up chai-enzyme properly. I’ve created a demo repo to reproduce this.

Before: https://github.com/ayrton/chai-enzyme-issue-92/commit/1286f417df8c60887711149224587402a4665f2c

$ npm test

> chai-enzyme-issue-92@1.0.0 test /Users/adc/Developer/ayrton/chai-enzyme-issue-92
> mocha --require babel-core/register foo.test.js



  My Component
    ✓ works in enzyme
    1) but not in chai-enzyme


  1 passing (744ms)
  1 failing

  1) My Component but not in chai-enzyme:
     AssertionError: expected { Object (root, unrendered, ...) } to have a property '$$typeof'
      at Assertion.include (node_modules/chai/lib/chai/core/assertions.js:221:47)
      at Assertion.assert (node_modules/chai/lib/chai/utils/addChainableMethod.js:84:49)
      at Context.<anonymous> (foo.test.js:21:24)



npm ERR! Test failed.  See above for more details.

After: https://github.com/ayrton/chai-enzyme-issue-92/commit/5511d692ae18e987cb6f22f8438052baf49f2700

$ npm test

> chai-enzyme-issue-92@1.0.0 test /Users/adc/Developer/ayrton/chai-enzyme-issue-92
> mocha foo.test.js



  My Component
    ✓ works in enzyme
    ✓ but not in chai-enzyme


  2 passing (795ms)

[evandavis]

After re-installing my node_modules, I’ve simplified the example down to:

import React from 'react';
import {shallow} from 'enzyme';
import {expect} from 'chai';

function MyComponent() {
  return (
    <div>
      <div />
    </div>
  );
}

describe.only('My Component', function () {
  it('works in enzyme', () => {
    const wrapper = shallow(<MyComponent />);
    expect(wrapper.contains(<div />)).to.equal(true);
  });

  it('but not in chai-enzyme', () => {
    const wrapper = shallow(<MyComponent />);
    expect(wrapper).to.contain(<div />);
  });
});

which I run with

./node_modules/mocha/bin/mocha --require babel-core/register foo.test.js

and I get the same results. The .to.contain test fails.