tests/testthat/test-dt_pivot_wider.R

In tidyfast: Fast Tidying of Data

# tests from tidyr regarding pivot_wider

test_that("can pivot all cols to wide", {
  df <- data.table(label = c("x", "y", "z"), val = 1:3)
  pivot_df <- dt_pivot_wider(df, names_from = label, values_from = val)

  expect_named(pivot_df, c("x", "y", "z"))
  expect_equal(nrow(pivot_df), 1)
})


test_that("non-pivoted cols are preserved", {
  df <- data.table(a = 1, label = c("x", "y"), val = 1:2)
  pivot_df <- dt_pivot_wider(df, names_from = label, values_from = val)

  expect_named(pivot_df, c("a", "x", "y"))
  expect_equal(nrow(pivot_df), 1)
})

test_that("implicit missings turn into explicit missings", {
  df <- data.table(a = 1:2, label = c("x", "y"), val = 1:2)
  pivot_df <- dt_pivot_wider(df, names_from = label, values_from = val)

  expect_equal(pivot_df$a, c(1, 2))
  expect_equal(pivot_df$x, c(1, NA))
  expect_equal(pivot_df$y, c(NA, 2))
})

test_that("can override default keys", {
  df <- dplyr::tribble(
    ~row, ~name, ~var, ~value,
    1,    "Sam", "age", 10,
    2,    "Sam", "height", 1.5,
    3,    "Bob", "age", 20,
  )

  pv <- dt_pivot_wider(df, id_cols = name, names_from = var, values_from = value)
  expect_equal(nrow(pv), 2)
})

# multiple values ----------------------------------------------------------

test_that("can pivot from multiple measure cols", {
  df <- data.table(row = 1, var = c("x", "y"), a = 1:2, b = 3:4)
  pv <- dt_pivot_wider(df, names_from = var, values_from = c(a, b))

  expect_named(pv, c("row", "a_x", "a_y", "b_x", "b_y"))
  expect_equal(pv$a_x, 1)
  expect_equal(pv$b_y, 4)
})

test_that("can pivot from multiple measure cols using all keys", {
  df <- data.table(var = c("x", "y"), a = 1:2, b = 3:4)
  pv <- dt_pivot_wider(df, names_from = var, values_from = c(a, b))

  expect_named(pv, c("a_x", "a_y", "b_x", "b_y"))
  expect_equal(pv$a_x, 1)
  expect_equal(pv$b_y, 4)
})

# select helpers ----------------------------------------------------------

test_that("can pivot from multiple measure cols using helpers", {
  df <- data.table(row = 1, var = c("x", "y"), a = 1:2, b = 3:4)
  pv <- dt_pivot_wider(df,
                       names_from = var,
                       values_from = c(dt_starts_with("a"), dt_ends_with("b")))

  expect_named(pv, c("row", "a_x", "a_y", "b_x", "b_y"))
  expect_equal(pv$a_x, 1)
  expect_equal(pv$b_y, 4)
})