test_that("make_ works, order of arguments does not matter", {
  g0 <- make_undirected_graph(1:10)
  g1 <- make_(undirected_graph(1:10))
  g2 <- make_(undirected_graph(), 1:10)
  g3 <- make_(1:10, undirected_graph())

  expect_true(identical_graphs(g0, g1))
  expect_true(identical_graphs(g0, g2))
  expect_true(identical_graphs(g0, g3))
})

test_that("sample_, graph_ also work", {
  g0 <- make_undirected_graph(1:10)
  g1 <- sample_(undirected_graph(1:10))
  g2 <- sample_(undirected_graph(), 1:10)
  g3 <- sample_(1:10, undirected_graph())

  expect_true(identical_graphs(g0, g1))
  expect_true(identical_graphs(g0, g2))
  expect_true(identical_graphs(g0, g3))

  g4 <- graph_(undirected_graph(1:10))
  g5 <- graph_(undirected_graph(), 1:10)
  g6 <- graph_(1:10, undirected_graph())

  expect_true(identical_graphs(g0, g4))
  expect_true(identical_graphs(g0, g5))
  expect_true(identical_graphs(g0, g6))
})

test_that("error messages are proper", {
  expect_error(make_(), "Don't know how to make_")
  expect_error(make_(1:10), "Don't know how to make_")

  expect_error(graph_(), "Don't know how to graph_")
  expect_error(graph_(1:10), "Don't know how to graph_")
  expect_error(
    graph_(directed_graph(), directed_graph()),
    "Don't know how to graph_"
  )

  expect_error(sample_(), "Don't know how to sample_")
  expect_error(sample_(1:10), "Don't know how to sample_")
  expect_error(
    sample_(directed_graph(), directed_graph()),
    "Don't know how to sample_"
  )
})

test_that("we pass arguments unevaluated", {
  g0 <- graph_from_literal(A -+ B:C)
  g1 <- graph_(from_literal(A -+ B:C))
  expect_true(identical_graphs(g0, g1))
})

test_that("graph_from_literal() and simple undirected graphs", {
  local_igraph_options(print.id = FALSE)
  expect_snapshot({
    graph_from_literal(A - B)
    graph_from_literal(A - B - C)
    graph_from_literal(A - B - C - A)
  })
})

test_that("graph_from_literal() and undirected explosion", {
  local_igraph_options(print.id = FALSE)
  expect_snapshot({
    graph_from_literal(A:B:C - D:E, B:D - C:E)
    graph_from_literal(A:B:C - D:E - F:G:H - I - J:K:L:M)
  })
})

test_that("graph_from_literal() and simple directed graphs", {
  local_igraph_options(print.id = FALSE)
  expect_snapshot({
    graph_from_literal(A -+ B)
    graph_from_literal(A -+ B -+ C)
    graph_from_literal(A -+ B -+ C -+ A)
    graph_from_literal(A -+ B +- C -+ A)
  })
})

test_that("graph_from_literal() and directed explosion", {
  local_igraph_options(print.id = FALSE)
  expect_snapshot({
    graph_from_literal(A:B:C -+ D:E, B:D +- C:E)
    graph_from_literal(A:B:C -+ D:E +- F:G:H -+ I +- J:K:L:M)
  })
})

test_that("graph_from_literal(simplify = FALSE)", {
  local_igraph_options(print.id = FALSE)
  expect_snapshot({
    graph_from_literal(1 - 1, 1 - 2, 1 - 2)
    graph_from_literal(1 - 1, 1 - 2, 1 - 2, simplify = FALSE)
  })
})