tests/testthat/test-rename_at.R

In recipes: Preprocessing and Feature Engineering Steps for Modeling

library(testthat)
library(recipes)

iris_rec <- recipe(~., data = iris)

test_that("basic usage", {
  rec <-
    iris_rec %>%
    step_rename_at(contains("Length"), fn = ~ tolower(.))

  prepped <- prep(rec, training = iris %>% slice(1:75))

  dplyr_train <-
    iris %>%
    as_tibble() %>%
    slice(1:75) %>%
    rename_at(vars(contains("Length")), ~ tolower(.))

  rec_train <- bake(prepped, new_data = NULL)
  expect_equal(dplyr_train, rec_train)

  dplyr_test <-
    iris %>%
    as_tibble() %>%
    slice(76:150) %>%
    rename_at(vars(contains("Length")), ~ tolower(.))
  rec_test <- bake(prepped, iris %>% slice(76:150))
  expect_equal(dplyr_test, rec_test)
})

test_that("mulitple functions", {
  rec <-
    iris_rec %>%
    step_rename_at(contains("Length"), fn = list(a = log, b = sqrt))

  expect_snapshot(error = TRUE,
                  prep(rec, training = iris %>% slice(1:75))
  )
})

test_that("no input", {
  # Wait for call pass through
  expect_error(
    iris_rec %>%
      step_rename_at() %>%
      prep(training = iris) %>%
      bake(new_data = NULL, composition = "data.frame")
  )
})

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

test_that("bake method errors when needed non-standard role columns are missing", {
  # Here for completeness
  # step_rename_at() is one of the thin wrappers around dplyr functions and
  # is thus hard to check against
  expect_true(TRUE)
})

test_that("empty printing", {
  rec <- recipe(mpg ~ ., mtcars)
  rec <- step_rename_at(rec, fn = identity)

  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_rename_at(rec1, fn = identity)

  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_rename_at(rec, fn = identity)

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

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

  rec <- prep(rec, mtcars)

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

test_that("printing", {
  rec <- recipe(~., data = iris) %>%
    step_rename_at(contains("Sepal"), fn = tolower)

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