nodeunit does not return

mongotests-sem.js

var q = require('q')
    , mongodb = require('mongodb')
    , Db = mongodb.Db
    , Server = mongodb.Server;

var server = 'localhost';
var port = 27017;
var dbconnections = [];
var sem = require('semaphore')(1);

function closedbconnections() {
    var i;
    for (i = 0; i < dbconnections.length; i++) {
        db = dbconnections[i];
        console.log(db.databaseName);
        try { db.close(); } catch (ex) { console.log(ex); }
    }
    console.log('closed ' + i + ' connections');
    dbconnections = [];
}

function listDatabases() {
    var defer = q.defer();
    getAuthenticatedDb('admin', 'admin', 'unittest')
    .then(function (db) {
        db.command({ 'listDatabases': 1 }, function (err, result) {
            if (err) { console.log(err); defer.reject(err); }
            else { defer.resolve(result.databases); }
        })
    });
    return defer.promise;
}

function dbShouldNotExists(name) {
    var defer = q.defer();
    listDatabases()
    .then(function (dbz) {
        dbz.forEach(function (db) {
            if (db.name == name) {
                defer.reject(db);
                return;
            }
        });
        defer.resolve();
    })
    .fail(function () {
        console.log('listdatabases failed');
        defer.reject();
    });
    return defer.promise;
}

function getDb(name) {
    var defer = q.defer();
    sem.take(function () {
      dbconnection = new Db(name, new Server(server, port, { 'poolSize': 1}), { safe: false });
      dbconnection.open(function (err, db) {
          sem.leave();
          if (err) {
              console.log(err);
              defer.reject(err);
          }
          else {
              dbconnections.push(dbconnection);
              defer.resolve(db);
          }
      });
    });
    return defer.promise;
}

function getAuthenticatedDb(name, username, pwd) {
    var defer = q.defer();
    getDb(name)
    .then(function(db) {
        db.authenticate(username, pwd, function (err, result) {
            if (err) {
                defer.reject(err);
            }
            else {
                defer.resolve(db);
            }
        });
    });
    return defer.promise;
}

exports.Test = {

    'dropdbs': function (test) {
        test.expect(1);
        q.all([
            dbShouldNotExists('test1'),
            dbShouldNotExists('test2'),
            dbShouldNotExists('test3')
        ])
        .then(function () {
            test.ok(true, '');
            return true;
        })
        .fail(function (reason) {
            console.log(reason);
        })
        .then(function () {
            closedbconnections();
            test.done();
        });
    }
}

mongotests.js

var q = require('q')
    , mongodb = require('mongodb')
    , Db = mongodb.Db
    , Server = mongodb.Server;

var server = 'localhost';
var port = 27017;
var dbconnections = [];

function closedbconnections() {
    var i;
    for (i = 0; i < dbconnections.length; i++) {
        db = dbconnections[i];
        console.log(db.databaseName);
        try { db.close(); } catch (ex) { console.log(ex); }
    }
    console.log('closed ' + i + ' connections');
    dbconnections = [];
}

function listDatabases() {
    var defer = q.defer();
    getAuthenticatedDb('admin', 'admin', 'unittest')
    .then(function (db) {
        db.command({ 'listDatabases': 1 }, function (err, result) {
            if (err) { console.log(err); defer.reject(err); }
            else { defer.resolve(result.databases); }
        })
    });
    return defer.promise;
}

function dbShouldNotExists(name) {
    var defer = q.defer();
    listDatabases()
    .then(function (dbz) {
        dbz.forEach(function (db) {
            if (db.name == name) {
                defer.reject(db);
                return;
            }
        });
        defer.resolve();
    })
    .fail(function () {
        console.log('listdatabases failed');
        defer.reject();
    });
    return defer.promise;
}

function getDb(name) {
    var defer = q.defer();
    dbconnection = new Db(name, new Server(server, port, { 'poolSize': 1}), { safe: false });
    dbconnection.open(function (err, db) {
        if (err) {
            console.log(err);
            defer.reject(err);
        }
        else {
            dbconnections.push(dbconnection);
            defer.resolve(db);
        }
    });
    return defer.promise;
}

function getAuthenticatedDb(name, username, pwd) {
    var defer = q.defer();
    getDb(name)
    .then(function(db) {
        db.authenticate(username, pwd, function (err, result) {
            if (err) {
                defer.reject(err);
            }
            else {
                defer.resolve(db);
            }
        });
    });
    return defer.promise;
}

exports.Test = {

    'dropdbs': function (test) {
        test.expect(1);
        q.all([
            dbShouldNotExists('test1'),
            dbShouldNotExists('test2'),
            dbShouldNotExists('test3')
        ])
        .then(function () {
            test.ok(true, '');
            return true;
        })
        .fail(function (reason) {
            console.log(reason);
        })
        .then(function () {
            closedbconnections();
            test.done();
        });
    }
}

test.js

var reporter = require('nodeunit').reporters.default;

exports['mongotests'] = require('./mongotests.js');

reporter.run(exports, null, function () {});