tests/testthat/test-dummy_extract.R

In tidymodels/recipes: Preprocessing and Feature Engineering Steps for Modeling

library(testthat)
library(recipes)

skip_if_not_installed("modeldata")
data(tate_text, package = "modeldata")

color_examples <- tibble(
  colors = c(
    "['red', 'blue']",
    "['red', 'blue', 'white']",
    "['blue', 'blue', 'blue']"
  )
)

color_result <- tribble(
  ~colors_blue, ~colors_red, ~colors_white, ~colors_other,
  1L,            1L,           0L,             0L,
  1L,            1L,           1L,             0L,
  3L,            0L,           0L,             0L
)

mini_tate <- tate_text[c(101, 102, 105, 108), ]

mini_tate_result <- tibble(
  medium_Charcoal = c(0L, 0L, 0L, 1L),
  medium_Etching =  c(1L, 1L, 1L, 0L),
  medium_aquatint = c(1L, 0L, 0L, 0L),
  medium_gouache =  c(0L, 0L, 0L, 1L),
  medium_paper =    c(1L, 1L, 1L, 1L),
  medium_other =    c(0L, 0L, 0L, 0L)
)

test_that("dummy variables", {
  # Using `sep` argument
  dummy <- recipe(~medium, data = mini_tate) %>%
    step_dummy_extract(medium, sep = "( and )|( on )", id = "")

  dummy_prepped <- prep(dummy)
  dummy_pred <- bake(dummy_prepped, new_data = mini_tate)

  expect_identical(dummy_pred, mini_tate_result)
  expect_identical(
    tidy(dummy_prepped, 1),
    tibble(
      terms = "medium",
      columns = c("paper", "Etching", "Charcoal", "aquatint", "gouache"),
      id = ""
    )
  )

  # Using `pattern` argument
  dummy <- recipe(~colors, data = color_examples) %>%
    step_dummy_extract(colors, pattern = "(?<=')[^',]+(?=')", id = "")

  dummy_prepped <- prep(dummy)
  dummy_pred <- bake(dummy_prepped, new_data = color_examples)

  expect_identical(dummy_pred, color_result)
  expect_identical(
    tidy(dummy_prepped, 1),
    tibble(
      terms = "colors",
      columns = gsub("colors_", "", names(color_result))[1:3],
      id = ""
    )
  )
})

test_that("other argument", {
  # Using `sep` argument
  dummy <- recipe(~medium, data = mini_tate) %>%
    step_dummy_extract(medium, sep = "( and )|( on )", id = "", other = "cake")

  dummy_prepped <- prep(dummy)
  dummy_pred <- bake(dummy_prepped, new_data = mini_tate)

  expect_identical(names(dummy_pred)[length(dummy_pred)], "medium_cake")
})

test_that("error when neither sep or pattern is specified", {
  expect_snapshot(
    error = TRUE,
    recipe(~medium, data = tate_text) %>%
      step_dummy_extract(medium) %>%
      prep()
  )
})

test_that("dummy variables with threshold", {
  # threshold = 0.5
  dummy <- recipe(~colors, data = color_examples) %>%
    step_dummy_extract(colors,
      pattern = "(?<=')[^',]+(?=')", id = "",
      threshold = 0.5
    )

  dummy_prepped <- prep(dummy)
  dummy_pred <- bake(dummy_prepped, new_data = color_examples)

  expect_identical(
    dummy_pred,
    color_result %>%
      mutate(colors_other = colors_other + colors_white) %>%
      select(-colors_white)
  )

  expect_identical(
    tidy(dummy_prepped, 1),
    tibble(
      terms = "colors",
      columns = gsub("colors_", "", names(color_result))[1:2],
      id = ""
    )
  )

  # threshold = 0.8
  dummy <- recipe(~colors, data = color_examples) %>%
    step_dummy_extract(colors,
      pattern = "(?<=')[^',]+(?=')", id = "",
      threshold = 0.8
    )

  dummy_prepped <- prep(dummy)
  dummy_pred <- bake(dummy_prepped, new_data = color_examples)

  expect_identical(
    dummy_pred,
    color_result %>%
      mutate(colors_other = colors_other + colors_white + colors_red) %>%
      select(-colors_white, -colors_red)
  )

  expect_identical(
    tidy(dummy_prepped, 1),
    tibble(
      terms = "colors",
      columns = gsub("colors_", "", names(color_result))[1],
      id = ""
    )
  )
})

test_that("dummy variables with integer threshold", {
  # threshold = 1
  dummy <- recipe(~colors, data = color_examples) %>%
    step_dummy_extract(colors,
      pattern = "(?<=')[^',]+(?=')", id = "",
      threshold = 1
    )

  dummy_prepped <- prep(dummy)
  dummy_pred <- bake(dummy_prepped, new_data = color_examples)

  expect_identical(
    dummy_pred,
    color_result
  )

  expect_identical(
    tidy(dummy_prepped, 1),
    tibble(
      terms = "colors",
      columns = gsub("colors_", "", names(color_result))[1:3],
      id = ""
    )
  )

  # threshold = 2
  dummy <- recipe(~colors, data = color_examples) %>%
    step_dummy_extract(colors,
      pattern = "(?<=')[^',]+(?=')", id = "",
      threshold = 2
    )

  dummy_prepped <- prep(dummy)
  dummy_pred <- bake(dummy_prepped, new_data = color_examples)

  expect_identical(
    dummy_pred,
    color_result %>%
      mutate(colors_other = colors_other + colors_white) %>%
      select(-colors_white)
  )

  expect_identical(
    tidy(dummy_prepped, 1),
    tibble(
      terms = "colors",
      columns = gsub("colors_", "", names(color_result))[1:2],
      id = ""
    )
  )

  # threshold = 3
  dummy <- recipe(~colors, data = color_examples) %>%
    step_dummy_extract(colors,
      pattern = "(?<=')[^',]+(?=')", id = "",
      threshold = 3
    )

  dummy_prepped <- prep(dummy)
  dummy_pred <- bake(dummy_prepped, new_data = color_examples)

  expect_identical(
    dummy_pred,
    color_result %>%
      mutate(colors_other = colors_other + colors_white + colors_red) %>%
      select(-colors_white, -colors_red)
  )

  expect_identical(
    tidy(dummy_prepped, 1),
    tibble(
      terms = "colors",
      columns = gsub("colors_", "", names(color_result))[1],
      id = ""
    )
  )
})

test_that("check_name() is used", {
  dat <- iris
  dat$Species_setosa <- dat$Species

  rec <- recipe(~., data = dat) %>%
    step_dummy_extract(Species, sep = " ")

  expect_snapshot(
    error = TRUE,
    prep(rec, training = dat)
  )
})

test_that("naming function", {
  expect_equal(
    dummy_extract_names("x", letters[c(1, 2, 3, 3)]),
    c("x_a", "x_b", "x_c", "x_c_2")
  )
  expect_equal(
    dummy_extract_names("x", letters[c(1, 2, 3, 3)], ordinal = TRUE),
    c("x_1", "x_2", "x_3", "x_4")
  )
})

test_that("case weights", {
  mini_tate_cw <- mini_tate %>%
    mutate(wts = frequency_weights(c(1, 1, 1, 5)))

  dummy <- recipe(~medium + wts, data = mini_tate_cw) %>%
    step_dummy_extract(medium, sep = "( and )|( on )", id = "", threshold = 6)

  dummy_prepped <- prep(dummy)
  dummy_pred <- bake(dummy_prepped, new_data = mini_tate)

  exp_results <- tibble(
    medium_paper = c(1L, 1L, 1L, 1L),
    medium_other = c(2L, 1L, 1L, 2L)
  )

  expect_identical(dummy_pred, exp_results)
  expect_identical(
    tidy(dummy_prepped, 1),
    tibble(
      terms = "medium",
      columns = "paper",
      id = ""
    )
  )

  expect_snapshot(dummy_prepped)

  # importance weights are not considered
  mini_tate_cw <- mini_tate %>%
    mutate(wts = importance_weights(c(1, 1, 1, 5)))

  dummy <- recipe(~medium + wts, data = mini_tate_cw) %>%
    step_dummy_extract(medium, sep = "( and )|( on )", id = "", threshold = 6)

  dummy_prepped <- prep(dummy)
  dummy_pred <- bake(dummy_prepped, new_data = mini_tate)

  exp_results <- tibble(
    medium_other = c(3L, 2L, 2L, 3L)
  )

  expect_identical(dummy_pred, exp_results)
  expect_identical(
    tidy(dummy_prepped, 1),
    tibble(
      terms = character(),
      columns = character(),
      id = character()
    )
  )

  expect_snapshot(dummy_prepped)
})

# Infrastructure ---------------------------------------------------------------

test_that("bake method errors when needed non-standard role columns are missing", {
  dummy <- recipe(~medium, data = mini_tate) %>%
    step_dummy_extract(medium, sep = "( and )|( on )", id = "") %>%
    update_role(medium, new_role = "potato") %>%
    update_role_requirements(role = "potato", bake = FALSE)

  dummy_prepped <- prep(dummy)

  expect_snapshot(error = TRUE, bake(dummy_prepped, new_data = mini_tate[, 1:3]))
})

test_that("empty printing", {
  rec <- recipe(mpg ~ ., mtcars)
  rec <- step_dummy_extract(rec)

  expect_snapshot(rec)

  rec <- prep(rec, mtcars)

  expect_snapshot(rec)
})

test_that("empty selection prep/bake is a no-op", {
  rec1 <- recipe(mpg ~ ., mtcars)
  rec2 <- step_dummy_extract(rec1)

  rec1 <- prep(rec1, mtcars)
  rec2 <- prep(rec2, mtcars)

  baked1 <- bake(rec1, mtcars)
  baked2 <- bake(rec2, mtcars)

  expect_identical(baked1, baked2)
})

test_that("empty selection tidy method works", {
  rec <- recipe(mpg ~ ., mtcars)
  rec <- step_dummy_extract(rec)

  expect <- tibble(terms = character(), columns = character(), id = character())

  expect_identical(tidy(rec, number = 1), expect)

  rec <- prep(rec, mtcars)

  expect_identical(tidy(rec, number = 1), expect)
})

test_that("keep_original_cols works", {
  new_names <- paste0("colors_", c("blue", "red", "white", "other"))

  rec <- recipe(~ colors, data = color_examples) %>%
    step_dummy_extract(colors, pattern = "(?<=')[^',]+(?=')",
                       keep_original_cols = FALSE)

  rec <- prep(rec)
  res <- bake(rec, new_data = NULL)

  expect_equal(
    colnames(res),
    new_names
  )

  rec <- recipe(~ colors, data = color_examples) %>%
    step_dummy_extract(colors, pattern = "(?<=')[^',]+(?=')",
                       keep_original_cols = TRUE)

  rec <- prep(rec)
  res <- bake(rec, new_data = NULL)

  expect_equal(
    colnames(res),
    c("colors", new_names)
  )
})

test_that("keep_original_cols - can prep recipes with it missing", {
  rec <- recipe(~ colors, data = color_examples) %>%
    step_dummy_extract(colors, pattern = "(?<=')[^',]+(?=')")

  rec$steps[[1]]$keep_original_cols <- NULL

  expect_snapshot(
    rec <- prep(rec)
  )

  expect_no_error(
    bake(rec, new_data = color_examples)
  )
})

test_that("printing", {
  rec <- recipe(~ medium, data = tate_text) %>%
    step_dummy_extract(all_predictors(), sep = ", ")

  expect_snapshot(print(rec))
  expect_snapshot(prep(rec))
})

test_that("bad args", {

  expect_snapshot(
    recipe(~colors, data = color_examples) %>%
      step_dummy_extract(colors, pattern = "(?<=')[^',]+(?=')", other = 2) %>%
      prep(),
    error = TRUE
  )
  expect_snapshot(
    recipe(~colors, data = color_examples) %>%
      step_dummy_extract(colors, pattern = "(?<=')[^',]+(?=')", other = 2) %>%
      prep(),
    error = TRUE
  )
  expect_snapshot(
    recipe(~colors, data = color_examples) %>%
      step_dummy_extract(colors, pattern = "(?<=')[^',]+(?=')", sep = 2) %>%
      prep(),
    error = TRUE
  )
  expect_snapshot(
    recipe(~colors, data = color_examples) %>%
      step_dummy_extract(colors, pattern = 2) %>%
      prep(),
    error = TRUE
  )
  expect_snapshot(
    recipe(~colors, data = color_examples) %>%
      step_dummy_extract(colors, pattern = "(?<=')[^',]+(?=')", naming = NULL) %>%
      prep(),
    error = TRUE
  )
})