tests/testthat/test-dataset-mnist.R

In mlverse/torchvision: Models, Datasets and Transformations for Images

context("dataset-mnist")

test_that("tests for the mnist dataset", {

  dir <- tempfile(fileext = "/")

  expect_error(
    ds <- mnist_dataset(dir)
  )

  ds <- mnist_dataset(dir, download = TRUE)

  i <- ds[1]
  expect_equal(dim(i[[1]]), c(28, 28))
  expect_equal(i[[2]], 6)
  expect_equal(length(ds), 60000)

  ds <- mnist_dataset(dir, transform = transform_to_tensor)
  dl <- torch::dataloader(ds, batch_size = 32)
  expect_length(dl, 1875)
  iter <- dataloader_make_iter(dl)
  i <- dataloader_next(iter)
  expect_tensor_shape(i[[1]], c(32, 1, 28, 28))
  expect_tensor_shape(i[[2]], 32)
  expect_true((torch_max(i[[1]]) <= 1)$item())
  expect_named(i, c("x", "y"))

})


test_that("tests for the kmnist dataset", {

  dir <- tempfile(fileext = "/")

  expect_error(
    ds <- kmnist_dataset(dir)
  )

  ds <- kmnist_dataset(dir, download = TRUE)

  i <- ds[1]
  expect_equal(dim(i[[1]]), c(28, 28))
  expect_equal(i[[2]], 9)
  expect_equal(length(ds), 60000)

  ds <- kmnist_dataset(dir, transform = transform_to_tensor)
  dl <- torch::dataloader(ds, batch_size = 32)
  expect_length(dl, 1875)
  iter <- dataloader_make_iter(dl)
  i <- dataloader_next(iter)
  expect_tensor_shape(i[[1]], c(32, 1, 28, 28))
  expect_tensor_shape(i[[2]], 32)
  expect_true((torch_max(i[[1]]) <= 1)$item())
  expect_named(i, c("x", "y"))
})