### Question:
ArrayAddExpression extends ArrayUpdateExpression { public UpdateOperator getOp() { return op; } ArrayAddExpression(Path field, UpdateOperator op, List<RValueExpression> list); Path getField(); List<RValueExpression> getValues(); UpdateOperator getOp(); @Override JsonNode toJson(); static ArrayAddExpression fromJson(ObjectNode node); @Override int hashCode(); @Override boolean equals(Object obj);  }### Answer:
@Test public void testGetOp() { ArrayAddExpression instance = new ArrayAddExpression(Path.EMPTY, UpdateOperator._set, null); UpdateOperator expResult = UpdateOperator._set; UpdateOperator result = instance.getOp(); assertEquals(expResult, result); }