test_that("edge_betweenness works", {
  kite <- graph_from_literal(
    Andre - Beverly:Carol:Diane:Fernando,
    Beverly - Andre:Diane:Ed:Garth,
    Carol - Andre:Diane:Fernando,
    Diane - Andre:Beverly:Carol:Ed:Fernando:Garth,
    Ed - Beverly:Diane:Garth,
    Fernando - Andre:Carol:Diane:Garth:Heather,
    Garth - Beverly:Diane:Ed:Fernando:Heather,
    Heather - Fernando:Garth:Ike,
    Ike - Heather:Jane,
    Jane - Ike
  )

  bet <- betweenness(kite)
  ebet <- edge_betweenness(kite)

  bet2 <- sapply(1:vcount(kite), function(x) {
    ae <- E(kite)[.inc(x)]
    (sum(ebet[ae]) - vcount(kite) + 1) / 2
  })

  expect_that(unname(bet), equals(bet2))

  #### Weighted

  E(kite)$weight <- sample(1:10, ecount(kite), replace = TRUE)

  bet <- betweenness(kite)
  ebet <- edge_betweenness(kite)
  bet2 <- sapply(1:vcount(kite), function(x) {
    ae <- E(kite)[.inc(x)]
    (sum(ebet[ae]) - vcount(kite) + 1) / 2
  })

  expect_that(unname(bet), equals(bet2))
})