mongo/jstests/disk/dbNoCreate.js

var baseName = "jstests_dbNoCreate";

var m = MongoRunner.runMongod({});

var t = m.getDB( baseName ).t;

assert.eq( 0, t.find().toArray().length );
t.remove({});
t.update( {}, { a:1 } );
t.drop();

MongoRunner.stopMongod(m);

m = MongoRunner.runMongod({restart:true, cleanData:false, dbpath: m.dbpath});
assert.eq( -1, 
           m.getDBNames().indexOf( baseName ), 
           "found " + baseName + " in " + tojson(m.getDBNames()));