code: public MockRouteTable createRouteTable(
              final String cidrBlock, final String vpcId) {
  
          MockRouteTable ret = new MockRouteTable();
          ret.setRouteTableId(
                  "rtb-" + UUID.randomUUID().toString().substring(0, ROUTETABLE_ID_POSTFIX_LENGTH));
          ret.setVpcId(vpcId);
          MockRoute mockRoute = new MockRoute();
          mockRoute.setGatewayId("local");
          mockRoute.setDestinationCidrBlock(cidrBlock);
          mockRoute.setState("active");
          mockRoute.setOrigin("CreateRouteTable");
          List<MockRoute> routeSet = new ArrayList<MockRoute>();
          routeSet.add(mockRoute);
          ret.setRouteSet(routeSet);
  
          allMockRouteTables.put(ret.getRouteTableId(), ret);
          return ret;
      }
docs: Create the mock RouteTable.
  @param cidrBlock VPC cidr block.
  @param vpcId vpc Id for RouteTable.
  @return mock RouteTable.