crew_test("autoscale() and descale() for single controllers", {
  x <- crew_controller_local(seconds_interval = 0.5, tasks_max = 1L)
  x$push(Sys.sleep(2L), scale = FALSE)
  x$push(Sys.sleep(2L), scale = FALSE)
  x$push(Sys.sleep(2L), scale = FALSE)
  expect_null(x$loop)
  x$autoscale()
  expect_true(inherits(x$loop, "event_loop"))
  # Manually wait in the global event loop at least 10 seconds.
  expect_equal(x$resolved(), 3L)
  x$descale()
  expect_null(x$loop)
  x$push(4L, scale = FALSE)
  x$push(5L, scale = FALSE)
  # Manually wait to verify no new workers or tasks are running.
  expect_equal(as.integer(x$client$status()["awaiting"]), 2L)
  expect_equal(x$resolved(), 3L)
  x$terminate()
})

crew_test("autoscale() and descale() for controller groups", {
  y <- crew_controller_local(seconds_interval = 0.5, tasks_max = 1L)
  x <- crew::crew_controller_group(y, seconds_interval = 0.5)
  x$push(Sys.sleep(2L), scale = FALSE)
  x$push(Sys.sleep(2L), scale = FALSE)
  x$push(Sys.sleep(2L), scale = FALSE)
  expect_null(y$loop)
  x$autoscale()
  expect_true(inherits(y$loop, "event_loop"))
  # Manually wait in the global event loop at least 10 seconds.
  expect_equal(x$resolved(), 3L)
  x$descale()
  expect_null(y$loop)
  x$push(4L, scale = FALSE)
  x$push(5L, scale = FALSE)
  # Manually wait to verify no new workers or tasks are running.
  expect_equal(as.integer(y$client$status()["awaiting"]), 2L)
  expect_equal(x$resolved(), 3L)
  x$terminate()
})