How to test children components get proper context from parent's getChildContext()?

The tab:

function _handleTabChange(eventKey, id, tabsChange, e) {
  e.preventDefault();
  tabsChange({ id, eventKey });
}

const _Tab = ({ eventKey, children, ...props }, { activeKey, parentContainer, tabsChange }) => (
  <li className={classNames('b-tab', { active: eventKey === activeKey })} {...props}>
    <a href="#"
      role="tab"
      data-toggle="tab"
      onClick={_handleTabChange.bind(this, eventKey, parentContainer, tabsChange)}>
      {children}
    </a>
  </li>
);

The Tab Container:

class _TabContainer extends Component {

  static displayName = 'TabContainer'

  static propTypes = {
    children: PropTypes.node.isRequired,
    tabsAddContainer: PropTypes.func.isRequired,
    tabsRemoveContainer: PropTypes.func.isRequired,
    tabsChange: PropTypes.func.isRequired,
    tabs: PropTypes.object.isRequired,
    tabContainerID: PropTypes.string,
  }

  static childContextTypes = {
    parentContainer: PropTypes.string.isRequired,
    tabsChange: PropTypes.func.isRequired,
    activeKey: PropTypes.number.isRequired,
  }

  constructor(props) {
    super(props);
    this.clones = Children.map(this.props.children, (element, eventKey) => {
      if (element.props.active) {
        this.defaultActive = eventKey;
      }
      console.log("defaultActive", this.defaultActive);
      return cloneElement(element, { eventKey });
    });
  }

  getChildContext() {
    const { tabContainerID, tabsChange, tabs } = this.props;
    //activeKey is tabs[tabContainerID] unless it hasn't been instantiated, in which case
    //it is the defaultActive gathered by mapping over Tabs to find one with an active prop
    const activeKey = (tabs && tabs[tabContainerID] && tabs[tabContainerID] !== '') ?
      tabs[tabContainerID] :
      this.defaultActive;
    return {
      parentContainer: tabContainerID,
      activeKey,
      tabsChange,
    };
  }

  componentWillMount() {
    const { tabContainerID, tabsAddContainer } = this.props;
    if (tabContainerID) {
      tabsAddContainer({ tabContainerID, defaultActive: this.defaultActive });
    }
  }

  componentWillUnmount() {
    const { tabContainerID, tabsRemoveContainer } = this.props;
    if (tabContainerID) {
      tabsRemoveContainer(tabContainerID);
    }
  }

  defaultActive = 0;

  render() {
    const { children, tabsChange, ...restProps } = this.props;
    return (
      <div {...restProps} className='tab-container'>
        <ul className='nav nav-tabs nav-default' role='tablist'>
          {this.clones}
        </ul>
      </div>
    );
  }
}