expect-element.js

expect.extend({
  toContainElement(instance, targetElement) {
    let matchingElements = instance.findAllByProps(targetElement.props);

    if (matchingElements.length === 0) {
      return {
        message() {
          let props = JSON.stringify(targetElement.props);
          return `expected to find element with props ${props}`;
        },
        pass: false
      };
    }

    let matchedElement = matchingElements.find(
      element => element.type === targetElement.type
    );

    if (matchedElement == null) {
      return {
        message() {
          let type = targetElement.type.displayName || targetElement.type.name;
          return `expected to find element with type ${type}`;
        },
        pass: false
      };
    }

    return {
      message() {
        let type = targetElement.type.displayName || targetElement.type.name;
        return `expected not to find element with type ${type}`;
      },
      pass: true
    };
  }
});

// use it like:

import { create } from 'react-test-renderer';

let renderer = create(<div>hi</div>);

expect(renderer.root).toContainElement(<div>hi</div>);