t = db.eval5;
t.drop();

t.save( { a : 1 , b : 2 , c : 3 } );

assert.eq( 3 , 
           db.eval( 
               function(z){
                   return db.eval5.find().toArray()[0].c;
               }
           ) , 
           "something weird A"
         );

assert.isnull( 
           db.eval( 
               function(z){
                   return db.eval5.find( {} , { a : 1 } ).toArray()[0].c;
               }
           ),
        "field spec didn't work" 
      );