spyOn(markdownDatasets, 'getAggregations').and.returnValue(
      Immutable.fromJS([
        { key: 'id1', label: 'label1', filtered: { doc_count: 25 } },
        { key: 'id2', label: 'label2', filtered: { doc_count: 33 } },
        { key: 'missing', label: 'No value', filtered: { doc_count: 45 } },