simulateError.md

.simulateError(error) => Self

Simulate a component throwing an error as part of its rendering lifecycle.

This is particularly useful in combination with React 16 error boundaries (ie, the componentDidCatch and static getDerivedStateFromError lifecycle methods).

Arguments

1. error (Any): The error to throw.

Returns

ReactWrapper: Returns itself.

Example

function Something() {
  // this is just a placeholder
  return null;
}

class ErrorBoundary extends React.Component {
  static getDerivedStateFromError(error) {
    return {
      hasError: true,
    };
  }

  constructor(props) {
    super(props);
    this.state = { hasError: false };
  }

  componentDidCatch(error, info) {
    const { spy } = this.props;
    spy(error, info);
  }

  render() {
    const { children } = this.props;
    const { hasError } = this.state;
    return (
      <React.Fragment>
        {hasError ? 'Error' : children}
      </React.Fragment>
    );
  }
}
ErrorBoundary.propTypes = {
  children: PropTypes.node.isRequired,
  spy: PropTypes.func.isRequired,
};

const spy = sinon.spy();
const wrapper = mount(<ErrorBoundary spy={spy}><Something /></ErrorBoundary>);
const error = new Error('hi!');
wrapper.find(Something).simulateError(error);

expect(wrapper.state()).to.have.property('hasError', true);
expect(spy).to.have.property('callCount', 1);
expect(spy.args).to.deep.equal([
  error,
  {
    componentStack: `
    in Something (created by ErrorBoundary)
    in ErrorBoundary (created by WrapperComponent)
    in WrapperComponent`,
  },
]);