context("drop variables")

test_that("test basic functionality", {
  dt <- data.table(sapply(setNames(letters, letters), function(x) {
    assign(x, rnorm(100))
  }))
  dt2 <- copy(dt)
  n <- nrow(dt)
  drop_columns(dt, letters[2:25])
  drop_columns(dt2, seq(2, 25))
  expect_equal(dim(dt), c(n, 2))
  expect_equal(names(dt), c("a", "z"))
  expect_equal(dim(dt2), c(n, 2))
  expect_equal(names(dt2), c("a", "z"))
})

test_that("test non-data.table objects", {
  df <- data.frame(sapply(setNames(letters, letters), function(x) {
    assign(x, rnorm(10))
  }))
  expect_equal(class(drop_columns(df, 2:25)), class(df))
  expect_equal(names(drop_columns(df, 2:25)), c("a", "z"))
  expect_equal(dim(drop_columns(df, 2:25)), c(nrow(df), 2))
})