t = db.where3;
t.drop();

t.save( { returned_date : 5 } );
t.save( { returned_date : 6 } );

assert.eq( 1, t.find(function(){ return this.returned_date == 5; }).count(), "A" );
assert.eq( 1, t.find({ $where : "return this.returned_date == 5;" }).count(), "B" );
assert.eq( 1, t.find({ $where : "this.returned_date == 5;" }).count(), "C" );
assert.eq( 1, t.find({ $where : "(this.returned_date == 5);" }).count(), "D" );
assert.eq( 1, t.find({ $where : "((this.returned_date == 5) && (5 == 5));"}).count(), "E" );
assert.eq( 1, t.find({ $where : "x=this.returned_date;x == 5;" }).count(), "F" );