test_that("AcqFunction API works", {
  inst = MAKE_INST_1D()
  surrogate = SurrogateLearner$new(REGR_FEATURELESS, archive = inst$archive)

  acqf = AcqFunction$new(id = "acqf", constants = ParamSet$new(), surrogate = surrogate, requires_predict_type_se = FALSE, direction = "same", packages = "mlr3mbo", label = "label", man = "man")

  expect_r6(acqf$codomain, "ParamSet")
  expect_equal(acqf$codomain$ids(), "acqf")
  expect_equal(acqf$surrogate_max_to_min, c(y = 1))
  expect_equal(acqf$direction, "same")
  expect_equal(acqf$domain, inst$search_space)
  expect_learner(acqf$surrogate$learner)
  expect_equal(acqf$requires_predict_type_se, FALSE)
  expect_equal(acqf$packages, "mlr3mbo")
  expect_equal(acqf$label, "label")
  expect_equal(acqf$man, "man")
})

test_that("AcqFunction requires_predict_type_se works", {
  inst = MAKE_INST_1D()
  surrogate = SurrogateLearner$new(REGR_FEATURELESS, archive = inst$archive)
  surrogate$learner$predict_type = "response"

  expect_error(AcqFunction$new(id = "acqf", constants = ParamSet$new(), surrogate = surrogate, requires_predict_type_se = TRUE, direction = "same"), 'requires the surrogate to have `"se"`')
  surrogate$learner$predict_type = "se"
  acqf = AcqFunction$new(id = "acqf", constants = ParamSet$new(), surrogate = surrogate, requires_predict_type_se = TRUE, direction = "same")
  expect_error({acqf$surrogate$learner$predict_type = "response"}, 'requires the surrogate to have `"se"`')
  expect_error({acqf$requires_predict_type_se = FALSE}, "is read-only")
})

test_that("AcqFunction packages works", {
  inst = MAKE_INST_1D()
  surrogate = SurrogateLearner$new(REGR_FEATURELESS, archive = inst$archive)

  expect_warning(AcqFunction$new(id = "acqf", constants = ParamSet$new(), surrogate = surrogate, packages = "TestPackageThatDoesNotExist", requires_predict_type_se = FALSE, direction = "same"), "required but not installed for acquisition function")
  acqf = AcqFunction$new(id = "acqf", constants = ParamSet$new(), surrogate = surrogate, packages = "mlr3mbo", requires_predict_type_se = FALSE, direction = "same")
  expect_equal(acqf$packages, "mlr3mbo")
})