test_that("read of data works", {
  file <- paste0(tempdir(), "/test.csv")
  data <- data.frame("a" = c("2020-01-01", "2020-01-02"), "b" = 1:2)
  write.csv(data, file)
  controls <- list(
    data = list(
      file = file,
      date_column = "a",
      data_column = "b"
    )
  )
  controls <- set_controls(controls)
  out <- prepare_data(controls)
  expect_equal(out$dates, data$a)
  expect_equal(out$time_points, NA)
  expect_null(out$markov_chain)
  expect_equal(out$data, data$b)
  expect_equal(out$time_series, data$b)
  expect_null(out$T_star)
  expect_equal(out$controls, controls)
})