tests/testthat/test-dummy.R

In recipes: Preprocessing and Feature Engineering Steps for Modeling

library(testthat)
library(recipes)

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

sacr <- Sacramento

sacr$city <- as.character(sacr$city)
sacr$zip <- as.character(sacr$zip)

set.seed(1)
sacr$city[sample(1:nrow(sacr), 20)] <- NA_character_

sacr_missing <- sacr

sacr$city[is.na(sacr$city)] <- "missing"
sacr <- sacr[complete.cases(sacr), -3]

sacr_fac <- sacr
sacr_fac$city <- factor(sacr_fac$city)
sacr_fac$zip <- factor(sacr_fac$zip)

test_that("dummy variables with factor inputs", {
  rec <- recipe(sqft ~ zip + city, data = sacr_fac)
  dummy <- rec %>% step_dummy(city, zip, id = "")
  dummy_trained <- prep(dummy, training = sacr_fac, verbose = FALSE, strings_as_factors = FALSE)
  dummy_pred <- bake(dummy_trained, new_data = sacr_fac, all_predictors())

  expect_false(any(colnames(dummy_pred) == "city"))
  expect_false(any(colnames(dummy_pred) == "zip"))

  dummy_pred <- dummy_pred[, order(colnames(dummy_pred))]
  dummy_pred <- as.data.frame(dummy_pred)
  rownames(dummy_pred) <- NULL

  exp_res <- model.matrix(sqft ~ zip + city, data = sacr_fac)[, -1]
  exp_res <- exp_res[, colnames(exp_res) != "sqft"]
  colnames(exp_res) <- gsub("^zip", "zip_", colnames(exp_res))
  colnames(exp_res) <- gsub("^city", "city_", colnames(exp_res))
  colnames(exp_res) <- make.names(colnames(exp_res))
  exp_res <- exp_res[, order(colnames(exp_res))]
  exp_res <- as.data.frame(exp_res)
  rownames(exp_res) <- NULL
  expect_equal(dummy_pred, exp_res, ignore_attr = TRUE)

  dum_tibble <-
    tibble(terms = c("city", "zip"), columns = rep(rlang::na_chr, 2), id = "")
  dum_tibble_prepped_1 <-
    tibble(
      terms = "city",
      columns = attributes(dummy_trained$steps[[1]]$levels$city)$values,
      id = ""
    ) %>% slice(-1)
  dum_tibble_prepped_2 <-
    tibble(
      terms = "zip",
      columns = attributes(dummy_trained$steps[[1]]$levels$zip)$values,
      id = ""
    ) %>% slice(-1)
  expect_equal(tidy(dummy, 1), dum_tibble)
  expect_equal(
    tidy(dummy_trained, 1),
    bind_rows(dum_tibble_prepped_1, dum_tibble_prepped_2)
  )
})

test_that("dummy variables with non-factor inputs", {
  rec <- recipe(sqft ~ zip + city, data = sacr)
  dummy <- rec %>% step_dummy(city, zip)

  expect_snapshot(error = TRUE,
    prep(dummy, training = sacr, verbose = FALSE, strings_as_factors = FALSE)
  )

  sacr_fac_ish <-
    sacr_fac %>%
    mutate(city = as.character(city))

  expect_snapshot(
    error = TRUE,
    recipe(sqft ~ zip + price + city, data = sacr_fac_ish) %>%
      step_dummy(city, zip, price) %>%
      prep(training = sacr_fac_ish, verbose = FALSE, strings_as_factors = FALSE)
  )
})

test_that("create double dummy variables", {
  rec <- recipe(sqft ~ zip + city, data = sacr_fac)
  dummy <- rec %>% step_dummy(city, zip, id = "")
  dummy_trained <- prep(dummy, training = sacr_fac, verbose = FALSE, strings_as_factors = FALSE)
  dummy_pred <- bake(dummy_trained, new_data = sacr_fac, all_predictors())
  expect_true(all(vapply(dummy_pred, is.double, logical(1))))
})

test_that("create all dummy variables", {
  rec <- recipe(sqft ~ zip + city + price, data = sacr_fac)
  dummy <- rec %>% step_dummy(city, zip, one_hot = TRUE, id = "")
  dummy_trained <- prep(dummy, training = sacr_fac, verbose = FALSE, strings_as_factors = FALSE)
  dummy_pred <- bake(dummy_trained, new_data = sacr_fac, all_predictors())
  dummy_pred <- dummy_pred[, order(colnames(dummy_pred))]
  dummy_pred <- as.data.frame(dummy_pred)
  rownames(dummy_pred) <- NULL

  exp_res <- NULL
  for (pred in c("city", "price", "zip")) {
    tmp <- model.matrix(as.formula(paste("~", pred, "+ 0")), data = sacr_fac)
    colnames(tmp) <- gsub(paste0("^", pred), paste0(pred, "_"), colnames(tmp))
    exp_res <- bind_cols(exp_res, as_tibble(tmp))
  }
  colnames(exp_res) <- make.names(colnames(exp_res))
  exp_res <- as.data.frame(exp_res)
  rownames(exp_res) <- NULL
  # TODO: need some help with this one
  # expect_equal(dummy_pred, exp_res, ignore_attr = TRUE)

  dum_tibble <-
    tibble(terms = c("city", "zip"), columns = rep(rlang::na_chr, 2), id = "")
  dum_tibble_prepped_1 <-
    tibble(
      terms = "city",
      columns = attributes(dummy_trained$steps[[1]]$levels$city)$values,
      id = ""
    )
  dum_tibble_prepped_2 <-
    tibble(
      terms = "zip",
      columns = attributes(dummy_trained$steps[[1]]$levels$zip)$values,
      id = ""
    )
  expect_equal(
    tidy(dummy_trained, 1),
    bind_rows(dum_tibble_prepped_1, dum_tibble_prepped_2)
  )
})

test_that("tests for issue #91", {
  rec <- recipe(~city, data = sacr)
  factors <- rec %>% step_dummy(city)
  factors <- prep(factors, training = sacr)
  factors_data_1 <- bake(factors, new_data = sacr)
  # Remove one category in city
  factors_data_2 <- bake(factors, new_data = sacr %>% filter(city != "SACRAMENTO"))
  expect_equal(names(factors_data_1), names(factors_data_2))

  # now with ordered factor

  sacr$ordered_city <- as.ordered(sacr$city)
  rec <- recipe(~ordered_city, data = sacr)
  orderedfac <- rec %>% step_dummy(ordered_city)
  orderedfac <- prep(orderedfac, training = sacr)
  ordered_data_1 <- bake(orderedfac, new_data = sacr)
  # Remove one category in city
  ordered_data_2 <- bake(orderedfac, new_data = sacr %>% filter(city != "SACRAMENTO"))
  expect_equal(names(ordered_data_1), names(ordered_data_2))
})

test_that("tests for NA values in factor", {
  rec <- recipe(~city, data = sacr_missing)
  factors <- rec %>% step_dummy(city)
  expect_snapshot(
    factors <- prep(factors, training = sacr_missing)
  )

  factors_data_0 <- bake(factors, new_data = NULL)
  expect_snapshot(
    factors_data_1 <- bake(factors, new_data = sacr_missing)
  )

  expect_true(
    all(complete.cases(factors_data_0) == complete.cases(sacr_missing[, "city"]))
  )
  expect_true(
    all(complete.cases(factors_data_1) == complete.cases(sacr_missing[, "city"]))
  )
})

test_that("tests for NA values in ordered factor", {
  sacr_ordered <- sacr_missing
  sacr_ordered$city <- as.ordered(sacr_ordered$city)
  rec <- recipe(~city, data = sacr_ordered)
  factors <- rec %>% step_dummy(city)
  expect_snapshot(
    factors <- prep(factors, training = sacr_ordered)
  )

  factors_data_0 <- bake(factors, new_data = NULL)
  expect_snapshot(
    factors_data_1 <- bake(factors, new_data = sacr_ordered)
  )

  expect_true(
    all(complete.cases(factors_data_0) == complete.cases(sacr_ordered[, "city"]))
  )
  expect_true(
    all(complete.cases(factors_data_1) == complete.cases(sacr_ordered[, "city"]))
  )
})



test_that("new levels", {
  df <- data.frame(
    y = c(1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0),
    x1 = c(
      "A", "B", "B", "B", "B", "A", "A", "A", "B", "A", "A", "B",
      "A", "C", "C", "B", "A", "B", "C", "A"
    ),
    stringsAsFactors = FALSE
  )
  training <- df[1:10, ]
  testing <- df[11:20, ]
  training$y <- as.factor(training$y)
  training$x1 <- as.factor(training$x1)
  testing$y <- as.factor(testing$y)
  testing$x1 <- as.factor(testing$x1)

  expect_snapshot(
    recipes:::warn_new_levels(testing$x1, levels(training$x1))
  )
  expect_silent(
    recipes:::warn_new_levels(training$x1, levels(training$x1))
  )

  rec <- recipe(y ~ x1, data = training) %>%
    step_dummy(x1)
  expect_silent(
    rec <- prep(rec, training = training)
  )
  expect_snapshot(
    bake(rec, new_data = testing)
  )
})

test_that("tests for issue #301", {
  rec <- recipe(~Species, data = iris)
  dummies <- rec %>% step_dummy(Species)
  dummies <- prep(dummies, training = iris)
  expect_equal(NULL, attr(dummies$steps[[1]]$levels$Species, ".Environment"))

  saved_recipe <- tempfile()
  saveRDS(dummies, file = saved_recipe)
  read_recipe <- readRDS(file = saved_recipe)
  unlink(saved_recipe)
  expect_equal(bake(dummies, new_data = iris), bake(read_recipe, new_data = iris))

  saved_dummies <- dummies
  saved_recipe <- tempfile()
  save(saved_dummies, file = saved_recipe)
  rm(saved_dummies)
  load(file = saved_recipe)
  unlink(saved_recipe)
  expect_equal(bake(dummies, new_data = iris), bake(saved_dummies, new_data = iris))
})

test_that("works with non-standard column names", {
  df <- tibble(`with space` = factor(letters[1:3]))

  expect_equal(
    recipe(~., data = df) %>%
      step_dummy(all_predictors()) %>%
      prep() %>%
      bake(new_data = NULL) %>%
      colnames(),
    c("with space_b", "with space_c")
  )

  expect_equal(
    recipe(~., data = df) %>%
      step_dummy(all_predictors(), one_hot = TRUE) %>%
      prep() %>%
      bake(new_data = NULL) %>%
      colnames(),
    c("with space_a", "with space_b", "with space_c")
  )
})

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

test_that("Deprecation warning", {
  expect_snapshot(error = TRUE,
    recipe(~ ., data = mtcars) %>%
      step_dummy(preserve = TRUE)
  )
})

test_that("no columns selected", {
  zdat <- tibble(
    y = c(1, 2, 3),
    x = c("a", "a", "a"),
    z = 3:1
  )

  rec <- recipe(y ~ ., data = zdat) %>%
    step_zv(all_predictors()) %>%
    step_dummy(all_nominal()) %>%
    prep(training = zdat)

  expect_null(rec$steps[[2]]$levels)

  expect_equal(names(bake(rec, zdat)), c("z", "y"))

  expect_snapshot(print(rec))

  exp_tidy <- tibble(terms = character(), columns = character(), id = character())
  expect_equal(exp_tidy, tidy(rec, number = 2))
})

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

  rec <- recipe(~., data = dat) |>
    step_dummy(Species)

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

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

test_that("bake method errors when needed non-standard role columns are missing", {
  rec <- recipe(sqft ~ zip + city, data = sacr_fac)
  dummy <- rec %>% step_dummy(city, zip, id = "") %>%
    update_role(city, zip, new_role = "potato") %>%
    update_role_requirements(role = "potato", bake = FALSE)
  dummy_trained <- prep(dummy, training = sacr_fac, verbose = FALSE, strings_as_factors = FALSE)

  expect_error(bake(dummy_trained, new_data = sacr_fac[, 3:4], all_predictors()),
               class = "new_data_missing_column")
})

test_that("empty printing", {
  rec <- recipe(mpg ~ ., mtcars)
  rec <- step_dummy(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(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(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 <- c("Species_versicolor", "Species_virginica")

  rec <- recipe(~ Species, iris) %>%
    step_dummy(all_predictors(), keep_original_cols = FALSE)

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

  expect_equal(
    colnames(res),
    new_names
  )

  rec <- recipe(~ Species, iris) %>%
    step_dummy(all_predictors(), keep_original_cols = TRUE)

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

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

test_that("keep_original_cols - can prep recipes with it missing", {
  rec <- recipe(~ Species, iris) %>%
    step_dummy(all_predictors())

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

  expect_snapshot(
    rec <- prep(rec)
  )

  expect_error(
    bake(rec, new_data = iris),
    NA
  )
})

test_that("printing", {
  rec <- recipe(sqft ~ ., data = sacr_fac) %>%
    step_dummy(city, zip)

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