testthat::test_that("setup_cachix(): error if already configured", {
  skip_if_not(nix_shell_available())
  testthat::expect_error(
    setup_cachix(nix_conf_path = "testdata/nix_conf_samples/nix_already/"), "already configured"
  )
})

testthat::test_that("setup_cachix(): error if no nix", {
  skip_if_not(!nix_shell_available())
  testthat::expect_error(
    setup_cachix(nix_conf_path = "testdata/nix_conf_samples/nix_already/"), "no need"
  )
})

testthat::test_that("setup_cachix(): configure if not already", {
  skip_if_not(nix_shell_available())
  testthat::expect_snapshot_file(
    path = setup_cachix(nix_conf_path = "testdata/nix_conf_samples/nix_not_yet/"),
    name = "nix.conf"
  )

  on.exit(
    unlink("testdata/nix_conf_samples/nix_not_yet/nix.conf"),
    add = TRUE
  )

  on.exit(
    file.copy(
      from = "testdata/nix_conf_samples/nix_not_yet/nix.conf-ground_truth",
      to = "testdata/nix_conf_samples/nix_not_yet/nix.conf",
    ),
    add = TRUE
  )
})