for (n_warm_up_iteration in c(0, 1, 10)) {
  for (n_main_iteration in c(0, 1, 10)) {
    for (dimension in c(1, 2)) {
      for (trace_warm_up in c(TRUE, FALSE)) {
        for (show_progress_bar in c(TRUE, FALSE)) {
          for (wrapped_initial_state in c(TRUE, FALSE)) {
            for (explicit_trace_function in c(TRUE, FALSE)) {
              test_that(
                sprintf(
                  paste0(
                    "Sampling chain with %i warm-up iterations, ",
                    "%i main iterations, dimension %i, ",
                    "trace_warm_up = %i, show_progress_bar = %i ",
                    "wrapped_initial_state = %i and ",
                    "explicit_trace_function = %i works"
                  ),
                  n_warm_up_iteration,
                  n_main_iteration,
                  dimension,
                  trace_warm_up,
                  show_progress_bar,
                  wrapped_initial_state,
                  explicit_trace_function
                ),
                {
                  target_distribution <- standard_normal_target_distribution()
                  if (explicit_trace_function) {
                    target_distribution[["trace_function"]] <- (
                      default_trace_function(target_distribution)
                    )
                  }
                  adapters <- list(
                    scale_adapter(
                      "stochastic_approximation",
                      initial_scale = 1.
                    )
                  )
                  withr::with_seed(default_seed(), {
                    position <- rnorm(dimension)
                  })
                  if (wrapped_initial_state) {
                    initial_state <- chain_state(position)
                  } else {
                    initial_state <- position
                  }
                  results <- sample_chain(
                    target_distribution = target_distribution,
                    initial_state = initial_state,
                    n_warm_up_iteration = n_warm_up_iteration,
                    n_main_iteration = n_main_iteration,
                    adapters = adapters,
                    trace_warm_up = trace_warm_up,
                    show_progress_bar = show_progress_bar
                  )
                  expected_results_names <- c(
                    "final_state", "traces", "statistics"
                  )
                  if (trace_warm_up) {
                    expected_results_names <- c(
                      expected_results_names,
                      "warm_up_traces",
                      "warm_up_statistics"
                    )
                  }
                  expect_named(
                    results,
                    expected_results_names,
                    ignore.order = TRUE,
                  )
                  expect_nrow(results$traces, n_main_iteration)
                  expect_ncol(results$traces, dimension + 1)
                  expect_nrow(results$statistics, n_main_iteration)
                  expect_ncol(results$statistics, 1)
                  if (trace_warm_up) {
                    expect_nrow(results$warm_up_traces, n_warm_up_iteration)
                    expect_ncol(results$warm_up_traces, dimension + 1)
                    expect_nrow(results$warm_up_statistics, n_warm_up_iteration)
                    expect_ncol(results$warm_up_statistics, 2)
                  }
                }
              )
            }
          }
        }
      }
    }
  }
}

test_that("Sample chains with invalid initial_state raises error", {
  target_distribution <- standard_normal_target_distribution()
  proposal <- barker_proposal()
  expect_error(
    sample_chain(
      target_distribution = target_distribution,
      proposal = proposal,
      initial_state = list(),
      n_warm_up_iteration = 1,
      n_main_iteration = 1,
    ),
    "initial_state"
  )
})

test_that("Sample chains with invalid target_distribution raises error", {
  expect_error(
    sample_chain(
      target_distribution = list(),
      initial_state = c(0., 0.),
      n_warm_up_iteration = 1,
      n_main_iteration = 1,
    ),
    "target_distribution"
  )
})