test_that("make_lattice works", {
  g <- make_lattice(dim = 2, length = 3, periodic = F)
  g2 <- make_empty_graph(n = 9) + edges(c(
    1, 2,
    1, 4,
    2, 3,
    2, 5,
    3, 6,
    4, 5,
    4, 7,
    5, 6,
    5, 8,
    6, 9,
    7, 8,
    8, 9
  ))
  expect_equal(as_edgelist(g), as_edgelist(g2))

  g <- make_lattice(dim = 2, length = 3, periodic = T)
  g2 <- make_empty_graph(n = 9) + edges(c(
    1, 2,
    1, 4,
    2, 3,
    2, 5,
    1, 3,
    3, 6,
    4, 5,
    4, 7,
    5, 6,
    5, 8,
    4, 6,
    6, 9,
    7, 8,
    1, 7,
    8, 9,
    2, 8,
    7, 9,
    3, 9
  ))
  expect_equal(as_edgelist(g), as_edgelist(g2))
})

test_that("make_lattice prints a warning for fractional length)", {
  expect_warning(make_lattice(dim = 2, length = sqrt(2000)), "`length` was rounded")

  suppressWarnings(g <- make_lattice(dim = 2, length = sqrt(2000)))
  g2 <- make_lattice(dim = 2, length = 45)
  expect_true(identical_graphs(g, g2))
})