test_that("Piecemeal runs a simple worker and collects results", {
  outdir <- tempfile("piecemeal_test_")
  sim <- piecemeal::init(outdir)
  sim$factorial(a = 1:2)$nrep(2)
  sim$worker(function(a, .seed) a + .seed)
  res <- sim$run(shuffle = FALSE)
  df <- sim$result_df()
  expect_equal(nrow(df), 4)
  expect_true(all(df$a %in% 1:2))
  expect_true(all(df$.seed %in% 1:2))
  unlink(outdir, recursive = TRUE)
})