context("empty graphs")

g <- make_empty_graph(directed = FALSE)

test_that("empty graphs are not all recognized as ANs", {
  expect_false(is_an(g))
  expect_false(is_dynamic_an(g))
})

g <- as_an(g, add.type.attribute = TRUE)

test_that("empty graphs with 'type' attributes are recognized as ANs", {
  expect_true(is_an(g))
  expect_true(is_dynamic_an(g))
})

test_that("triad census functions can handle empty graphs", {
  expect_equal(
    triad_census(g, add.names = FALSE),
    triad_census_an(g, add.names = FALSE),
    matrix(0L, nrow = 1, ncol = 1)
  )
  expect_equal(
    triad_census_difference(g, add.names = FALSE),
    matrix(0L, nrow = 8, ncol = 2)
  )
  expect_equal(
    triad_census_binary(g, add.names = FALSE),
    matrix(0L, nrow = 4, ncol = 2)
  )
})

test_that("global triad closure functions can handle empty graphs", {
  expect_true(is.nan(triad_closure_watts_strogatz(g)))
  expect_true(is.nan(triad_closure_opsahl(g)))
  expect_true(is.nan(triad_closure_liebig_rao_0(g)))
  expect_true(is.nan(triad_closure_liebig_rao_3(g)))
  expect_true(is.nan(triad_closure_exclusive(g)))
})