public void testRefTime() {
        ReferenceGroupSet ref = new ReferenceGroupSet();

        for( int i = 0; i < 100000; i++ ) {
            switch( mRand.nextInt( 4 ) ) {
            case 0:
            {
                int c = mRand.nextInt( 10 );
                int v = mRand.nextInt( 100 );

                ref.add( c, v );
                break;
            }

            case 1:
            {
                int c = mRand.nextInt( 10 );
                int v = mRand.nextInt( 100 );

                ref.remove( c, v );
                break;
            }

            case 2:
            {
                int c = mRand.nextInt( 10 );
                List<Integer> list = new ArrayList<Integer>( 8 );

                for( int j = 0; j < 8; j++ ) {
                    int v = mRand.nextInt( 100 );
                    list.add( v );
                    ref.add( c, v );
                }

                break;
            }

            case 3:
            {
                int c = mRand.nextInt( 10 );
                List<Integer> list = new ArrayList<Integer>( 8 );

                for( int j = 0; j < 8; j++ ) {
                    int v = mRand.nextInt( 100 );
                    list.add( v );
                    ref.remove( c, v );
                }

                break;
            }

            case 4:
            {
                if( mRand.nextInt( 5 ) == 0 ) {
                    int c = mRand.nextInt( 10 );
                    ref.clear( c );
                }

                break;
            }
            }
        }
    }