try {
              network.edgeConnectingOrNull(node, otherNode);
              fail();
            } catch (IllegalArgumentException expected) {
            }
            try {
              network.edgeConnecting(node, otherNode);
              fail();
            } catch (IllegalArgumentException expected) {
            }
        }

        boolean isSelfLoop = node.equals(otherNode);

          default:
            assertThat(network.hasEdgeConnecting(node, otherNode)).isTrue();
            try {
              network.edgeConnectingOrNull(node, otherNode);
              fail();
            } catch (IllegalArgumentException expected) {
            }
        }

        boolean isSelfLoop = node.equals(otherNode);
        boolean connected = !edgesConnecting.isEmpty();