assertThat(network.removeNode(nodeList.get(i))).isTrue();
      }

      assertThat(network.nodes()).isEmpty();
      assertThat(network.edges()).isEmpty(); // no edges can remain if there's no nodes
      AbstractNetworkTest.validateNetwork(network);

      Collections.shuffle(nodeList, gen);
      for (Integer node : nodeList) {
        assertThat(network.addNode(node)).isTrue();
      }

        assertThat(network.removeNode(nodeList.get(i))).isTrue();
      }

      assertThat(network.nodes()).isEmpty();
      assertThat(network.edges()).isEmpty(); // no edges can remain if there's no nodes
      AbstractNetworkTest.validateNetwork(network);

      Collections.shuffle(nodeList, gen);
      for (Integer node : nodeList) {
        assertThat(network.addNode(node)).isTrue();
      }