test_that("disparity_through_time() works", {
  skip_if_not_installed("dispRity")

  crinoids <- as.data.frame(demo_data$wright$matrix[[1]][, 1:2])
  crinoids$time <- "before extinction"
  crinoids$time[demo_data$wright$subsets$after$elements] <- "after extinction"
  crinoids$time <- factor(crinoids$time)
  attach(crinoids)
  gg <- disparity_through_time(time ~ V1 * V2,
    groups = time, aspect = c(2, 1), xlim = c(-.6, .6), ylim = c(-.5, .5),
    col.regions = "lightgreen", col.point = c("red", "blue")
  )
  expect_true(is(gg, "trellis"))
  expect_doppelganger_deeptime("disparity_through_time()", gg)
})
