tests/testthat/test-gather-shadow.R

In njtierney/ggmissing: Data Structures, Summaries, and Visualisations for Missing Data

df <- data.frame(x = c(NA, 1:4), y = c(NA, NA, 1:3))

test_that("gather_shadow returns a tibble or data.frame", {
  expect_s3_class(gather_shadow(df), "data.frame")
  expect_s3_class(gather_shadow(df), "tbl")
})

test_that("gather_shadow errors when given non dataframe or 0 entry", {
  expect_snapshot(
    error = TRUE,
    gather_shadow(0)
  )
  expect_snapshot(
    error = TRUE,
    gather_shadow(matrix(0))
  )
  expect_snapshot(
    error = TRUE,
    gather_shadow(NULL)
  )
})

test_that("The number of rows are the same after using gather_shadow", {
  expect_equal(nrow(gather_shadow(df)), nrow(df) * 2)
})

test_that("There are three columns in gather_shadow", {
  expect_equal(ncol(gather_shadow(df)), 3)
})

test_that("gather_shadow returns columns with right names", {
  expect_equal(names(gather_shadow(df)), c("case", "variable", "missing"))
})