@Before
    public void beforeEachScenario(final Scenario scenario) throws Exception {
        world.beforeEachScenario(scenario);
        stringParameters.clear();
        if (traversal != null) {
            traversal.close();
            traversal = null;
        }

        if (result != null) result = null;
        if (error != null) error = null;
    }
Some implementations of {@link VertexProperty} are not {@code Serializable} and may lead to test failures when passed as
parameters. One such instance is {@code HadoopVertexProperty}. This method detaches vertex properties as tests
should never require implementation-specific elements.
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/features/StepDefinition.java