test_that("stringsAsFactors doesn't affect results", {
  skip_if(as.integer(R.Version()$major) >= 4L, "stringsAsFactors only affects R <4.0")

  old <- getOption("stringsAsFactors")
  on.exit(options(stringsAsFactors = old), add = TRUE)

  dat.character <- data_frame(x = letters[5:1], y = 1:5)
  dat.factor <- data_frame(x = letters[5:1], y = 1:5)

  base <- ggplot(mapping = aes(x, y)) + geom_point()
  xlabels <- function(x) x$layout$panel_params[[1]]$x$get_labels()

  options(stringsAsFactors = TRUE)
  char_true <- ggplot_build(base %+% dat.character)
  factor_true <- ggplot_build(base %+% dat.factor)

  options(stringsAsFactors = FALSE)
  char_false <- ggplot_build(base %+% dat.character)
  factor_false <- ggplot_build(base %+% dat.factor)

  expect_equal(xlabels(char_true), letters[1:5])
  expect_equal(xlabels(char_false), letters[1:5])
  expect_equal(xlabels(factor_true), letters[1:5])
  expect_equal(xlabels(factor_false), letters[1:5])
})