@Test
    @FeatureRequirement(featureClass = GraphFeatures.class, feature = GraphFeatures.FEATURE_ORDERABILITY_SEMANTICS)
    public void testErrorPropagation() {
        final P ERROR = P.lt(Double.NaN);

        // Propagates Error to parent not()
        checkHasNext(false, g.inject(1).not(not(is(ERROR))));
        checkHasNext(false, g.inject(1).not(is(ERROR)));

        // Does not propagate Error through non-filter parent
        checkHasNext(true, g.inject(1).not(union((is(ERROR)))));
        checkHasNext(false, g.inject(1).union((is(ERROR))));
    }
Child traversals should propagate error states to their parent traversal if and only if the parent step is a
filter step.
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/TernaryBooleanLogicsTest.java