x <- data.frame(a = 1, b = 2)

test_that("insert_blank", {
  expect_identical(insert_blanks("a", NULL, x), c("a", "..after1", "b"))
  expect_identical(
    insert_blanks(tidyselect::everything(), NULL, x),
    c("a", "..after1", "b", "..after2")
  )
  expect_identical(
    insert_blanks(NULL, "a", x),
    c("..before1", "a", "b")
  )
  expect_identical(
    insert_blanks(NULL, c("a", "b"), x),
    c("..before1", "a", "..before2", "b")
  )
  expect_identical(
    insert_blanks("a", "b", x),
    c("a", "..after1", "..before1", "b")
  )
})

test_that("with_blanks is tested via test-as-flextable.R", {
  expect_true(TRUE)
})