@Parameterized.Parameters(name = "{0}({1},{2}) = {3}")
        public static Iterable<Object[]> data() {
            return new ArrayList<>(Arrays.asList(new Object[][]{
                    {Operator.addAll, null, null, null},
                    {Operator.addAll, new ArrayList<>(Arrays.asList(1,2,3)), null, Arrays.asList(1,2,3)},
                    {Operator.addAll, null, new ArrayList<>(Arrays.asList(1,2,3)), Arrays.asList(1,2,3)},
                    {Operator.addAll, new ArrayList<>(Arrays.asList(1,2,3)), new ArrayList<>(Arrays.asList(4,5,6)), Arrays.asList(1,2,3,4,5,6)},
            }));
        }
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/process/traversal/OperatorTest.java