Added test cases for the washing of the date arguments.
Added test cases for the washing of the date arguments.

tiborsimko/invenio-search,tiborsimko/invenio-records,tiborsimko/invenio-records,inveniosoftware/invenio-records,inveniosoftware/invenio-search,tiborsimko/invenio-search,inveniosoftware/invenio-records,inveniosoftware/invenio-search