test_that("out of bound error message", {
  x <- torch_tensor(1)

  funs <- list(
    torch_sum,
    torch_mean,
    torch_median,
    torch_max,
    torch_min,
    torch_cummax,
    torch_cummin,
    torch_mode,
    torch_size,
    torch_softmax,
    torch_std,
    torch_squeeze,
    torch_var
  )

  for (f in funs) {
    expect_error(
      f(x, dim = 2),
      regex = "Dimension out of range (expected to be in range of [-1, 1], but got 2)",
      fixed = TRUE
    )
  }

  for (f in funs) {
    expect_error(
      f(x, dim = -2),
      regex = "Dimension out of range (expected to be in range of [-1, 1], but got -2)",
      fixed = TRUE
    )
  }

  x <- torch_randn(size = rep(1, 10))

  for (f in funs) {
    expect_error(
      f(x, dim = 11),
      regex = "Dimension out of range (expected to be in range of [-10, 10], but got 11)",
      fixed = TRUE
    )
  }
})

test_that("more than 1 dim", {
  x <- torch_randn(2, 2, 2)

  expect_error(
    torch_sum(x, dim = c(1, 4)),
    regex = "Dimension out of range (expected to be in range of [-3, 3], but got 4)",
    fixed = TRUE
  )
})

test_that("dim1 & dim2", {
  x <- torch_randn(2, 2)

  expect_error(
    torch_transpose(x, 3, 1),
    regex = "Dimension out of range (expected to be in range of [-2, 2], but got 3)",
    fixed = TRUE
  )

  expect_error(
    torch_transpose(x, 2, 3),
    regex = "Dimension out of range (expected to be in range of [-2, 2], but got 3)",
    fixed = TRUE
  )

  expect_error(
    torch_diag_embed(x, dim1 = 4, dim2 = 1),
    "Dimension out of range (expected to be in range of [-3, 3], but got 4)",
    fixed = TRUE
  )

  expect_error(
    torch_diag_embed(x, dim1 = 3, dim2 = 4),
    "Dimension out of range (expected to be in range of [-3, 3], but got 4)",
    fixed = TRUE
  )
})

test_that("dimension x does not have size y", {
  a <- torch_randn(c(4, 3))
  b <- torch_randn(c(4, 3))

  expect_error(
    torch_cross(a, b, dim = 1),
    regex = "inputs dimension 1 must have length 3",
    fixed = TRUE
  )
})

test_that("indices error message", {
  x <- torch_randn(4, 4, 2)
  e <- torch_max_pool2d_with_indices(x, kernel_size = c(2, 2))

  i <- as_array(torch_max(e[[2]])$to(torch_int()))
  indices <- torch_ones_like(e[[2]])
  indices[1, ..] <- 35L

  expect_error(
    torch_max_unpool2d(e[[1]], indices = indices, output_size = c(4, 4)),
    paste0("Found an invalid max index: ", 35),
    fixed = TRUE
  )
})

test_that("torch_flatten dim error", {
  x <- torch_randn(2, 2)
  expect_error(
    torch_flatten(x, start_dim = 3),
    "Dimension out of range (expected to be in range of [-2, 2], but got 3)",
    fixed = TRUE
  )
})

test_that("index argument", {
  x <- torch_tensor(c(1, 2, 3))
  expect_equal(as_array(torch_select(x, 1, 1)), 1)

  expect_error(
    torch_select(x, 1, 4),
    regex = "index 4 out of range for tensor of size [3] at dimension 1",
    fixed = TRUE
  )
})

test_that("torch_nll_loss out of bound", {
  x <- torch_randn(1, 5)

  expect_error(
    torch_nll_loss(x, torch_tensor(0, dtype = torch_long())),
    regex = "Indexing starts at 1 but found a 0.",
    fixed = TRUE
  )

  expect_error(
    torch_nll_loss(x, torch_tensor(6, dtype = torch_long())),
    regex = "Target 6 is out of bounds.",
    fixed = TRUE
  )
})

test_that("tensordot error message", {
  a <- torch_arange(start = 1, end = 60)$reshape(c(3, 4, 5))
  b <- torch_arange(start = 1, end = 24)$reshape(c(4, 3, 2))

  expect_error(
    torch_tensordot(a, b, list(c(2, 1), c(1, 3))),
    regex = "contracted dimensions need to match, but first has size 3 in dim 1 and second has size 2 in dim 3",
    fixed = TRUE
  )
})

test_that("embedding returns a better error message", {
  e <- nn_embedding(10, 3)
  x <- torch_tensor(c(0, 1, 2, 3), dtype = torch_long())

  expect_error(
    e(x),
    regex = "Indexing starts at 1 but found a 0."
  )
})

test_that("movedim", {
  x <- torch_randn(3, 2, 1)

  expect_error(
    torch_movedim(x, 0, 1),
    regex = "Dimension is 1-based, but found 0.",
    class = "value_error"
  )

  expect_error(
    torch_movedim(x, 4, 3),
    regexp = "Dimension out of range (expected to be in range of [-3, 3], but got 4)",
    fixed = TRUE
  )
})

test_that("subsetting empty tensors", {
  
  x <- torch_tensor(integer())
  expect_error(
    x[1],
    regexp = "index 1 is out of bounds for dimension 1 with size 0",
    fixed = TRUE
  )
  
  expect_error(
    x[-1],
    regexp = "index -1 is out of bounds for dimension 1 with size 0",
    fixed = TRUE
  )
  
})

test_that("translate", {
  
  x <- torch_tensor(c(2), requires_grad = TRUE)
  x$register_hook(function(grad) {
    torch_tensor(1)$sum(dim = 4)
  })
  y <- 2 * x
  expect_error(
    y$backward(),
    regexp = "Dimension out of range (expected to be in range of [-1, 1], but got 4)",
    fixed = TRUE
  )
  
})

test_that("cat", {
  
  expect_error(
    torch_cat(list(torch_randn(8, 2, 7), torch_randn(8, 3, 7)), dim = 1),
    regex = "Sizes of tensors must match except in dimension 1. Expected size 2 but got size 3 for tensor number 2 in the list.",
    fixed = TRUE
  )
  
})