// SERVER-9385 ensure saving a document derived from bson->js conversion doesn't lose it's _id
t = db.server9385;
t.drop();

t.insert( { _id : 1, x : 1 } );
x = t.findOne();
x._id = 2;
t.save( x );

t.find().forEach( printjson );

assert.eq( 2, t.find().count() );
assert.eq( 2, t.find().itcount() );

assert( t.findOne( { _id : 1 } ), "original insert missing" );
assert( t.findOne( { _id : 2 } ), "save didn't work?" );