test_that("functions working with graphs do the right thing?", {
  join_list_tbl_1 <- tibble(
    lhs = c("tf_2", "tf_3", "tf_4", "tf_5", "tf_6"),
    rhs = c("tf_1", "tf_2", "tf_3", "tf_4", "tf_5"),
    rank = as.numeric(2:6),
    has_father = rep(TRUE, 5)
  )

  join_list_tbl_3 <- tibble::tribble(
    ~lhs   , ~rhs   , ~rank , ~has_father ,
    "tf_2" , "tf_3" ,     2 , TRUE        ,
    "tf_4" , "tf_3" ,     3 , TRUE        ,
    "tf_1" , "tf_2" ,     4 , TRUE        ,
    "tf_5" , "tf_4" ,     5 , TRUE        ,
    "tf_6" , "tf_5" ,     6 , TRUE
  )

  expect_identical_graph(
    graph_from_data_frame(
      tibble(
        tables = c("tf_1", "tf_2", "tf_2", "tf_3", "tf_4", "tf_5", "tf_6"),
        ref_tables = c("tf_2", "tf_7", "tf_3", "tf_4", "tf_5", "tf_6", "tf_7")
      ),
      directed = FALSE
    ),
    create_graph_from_dm(dm_for_filter_w_cycle())
  )

  expect_snapshot({
    attr(graph_edges(create_graph_from_dm(nyc_comp())), "vnames")
  })
})

test_that("empty graph", {
  g0 <- create_graph_from_dm(empty_dm())
  g1 <- create_graph_from_dm(dm(x = tibble(a = 1)))
  expect_snapshot({
    print(g0)
    print(g1)
  })
})