nodes <- data.frame(
  id = LETTERS[1:2],
  lon = 1:2,
  lat = 1:2
)

links <- data.frame(from = "A", to = "B")

test_gn <- geonetwork(links, nodes, directed = FALSE)

test_that("Plot geonetwork object", {
  expect_error(plot(test_gn), NA)
  expect_error(plot(test_gn, add = TRUE), NA)
  expect_error(plot(test_gn, add = FALSE), NA)
})