'test Query#slice not via where, where skip and limit params': function () {
   var query = new Query();
   query.slice('collection', 14, 10); // Return the 15th through 25th
   query._fields.should.eql({collection: {$slice: [14, 10]}});
 },
 'test Query#slice not via where, where just negative limit param': function () {
   var query = new Query();
   query.slice('collection', -5);
   query._fields.should.eql({collection: {$slice: -5}});
 },