React error - two children with the same key, `[]`

Running the `__tests__/dashboard.js` tests gives the following error message:

```
console.error
      Warning: Encountered two children with the same key, `[]`. Keys should be unique so that components maintain their identity across updates. Non-unique keys may cause children to be duplicated and/or omitted — the behavior is unsupported and could change in a future version.
```