test_that("all_shortest_paths works", {
  edges <- matrix(
    c(
      "s", "a", 2,
      "s", "b", 4,
      "a", "t", 4,
      "b", "t", 2,
      "a", "1", 1,
      "a", "2", 1,
      "a", "3", 2,
      "1", "b", 1,
      "2", "b", 2,
      "3", "b", 1
    ),
    byrow = TRUE, ncol = 3,
    dimnames = list(NULL, c("from", "to", "weight"))
  )
  edges <- as.data.frame(edges)
  edges[[3]] <- as.numeric(as.character(edges[[3]]))

  g <- graph_from_data_frame(as.data.frame(edges))

  sortlist <- function(list) {
    list <- lapply(list, sort)
    list <- lapply(list, as.vector)
    list[order(sapply(list, paste, collapse = "!"))]
  }

  sp1 <- all_shortest_paths(g, "s", "t", weights = NA)

  expect_that(
    sortlist(sp1$vpaths),
    equals(list(c(1, 2, 7), c(1, 3, 7)))
  )
  expect_that(
    sp1$nrgeo,
    equals(c(1, 1, 1, 1, 1, 1, 2))
  )

  sp2 <- all_shortest_paths(g, "s", "t")

  expect_that(
    sortlist(sp2$vpaths),
    equals(list(c(1, 2, 3, 4, 7), c(1, 2, 7), c(1, 3, 7)))
  )
  expect_that(sp2$nrgeo, equals(c(1, 1, 2, 1, 1, 1, 3)))

  ## TODO

  ## E(g)$weight <- E(g)$weight - 1
  ## all_shortest_paths(g, "s", "t")
})