to satisfy snapshot

  • <RenderedPreactElement> to satisfy snapshot

Under jest, you can use snapshots. Snapshot tests save a snapshot of the component as it is currently rendered to a .snapshot file under a directory __snapshots__. Note that the snapshots for unexpected-preact are saved to a different filename than those jest uses natively. This is because the format differs slightly.

Remember that to include snapshot support for the shallow and DOM renderers, you need to require unexpected-preact as require('unexpected-preact/jest')

class MyComponent extends Component {
  render () {
    return (
      <div className="parent" id="main">
        <span>one</span>
        <span>two</span>
        <span>three</span>
      </div>
    );
  }
}

We can validate it satisfies the snapshot when it's rendered. If no snapshot exists, it will be automatically created the first time it is run.

expect(<MyComponent />, 'when rendered', 'to satisfy snapshot');

If in the future the component output changes, the error will be highlighted (using the same error highlighting used in the rest of unexpected-react).

Once you have checked that the changes are correct, you can run jest -u to update the snapshot, or if running in watch mode, press u.

Events

Triggered events still works, and can be combined with matching snaphots.

e.g.

 
expect(<MyComponent />, 
  'when rendered',
  'with event click', 
  'to satisfy snapshot'
);

Matching

The snapshot matches in the same way as to have rendered, so new classes, attributes and child nodes are not treated as a difference. This can be advantageous when you want to add new features to a component, but expect the existing component to keep the same basic template.

If you'd prefer to match the template exactly (order of classes is still ignored), see the assertion to match snapshot.