@After
    public void tearDown() throws Exception {
        super.tearDown();
        Spark.create("local[4]");
        Spark.close();
        HadoopPools.close();
        KryoShimServiceLoader.close();
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
spark-gremlin/src/test/java/org/apache/tinkerpop/gremlin/spark/structure/io/SparkIoRegistryCheck.java