	@Test
	void verticalPartitioningTest() {

		final Settings settings = new Settings.Builder("testingDB").build();
		final DatabaseStatistics statistics = new DatabaseStatistics("testingDB");
		final VerticalPartitioningLoader vp_loader = new VerticalPartitioningLoader(settings, spark, statistics);
		vp_loader.load();
		final Dataset<Row> tables_list = spark.sql("SHOW tables");

		// there should be at least a table for each distinct property
		final long tables_count = tables_list.count();
		assert (tables_count > numberPredicates);
	}