skip_if_not_installed("truncreg")
skip_if_not_installed("survival")

data("tobin", package = "survival")
m1 <- truncreg::truncreg(durable ~ age + quant, data = tobin, subset = durable > 0)

test_that("model_info", {
  expect_true(model_info(m1)$is_linear)
})

test_that("find_predictors", {
  expect_identical(find_predictors(m1), list(conditional = c("age", "quant")))
  expect_identical(find_predictors(m1, flatten = TRUE), c("age", "quant"))
  expect_null(find_predictors(m1, effects = "random"))
})

test_that("find_response", {
  expect_identical(find_response(m1), "durable")
})

test_that("link_inverse", {
  expect_equal(link_inverse(m1)(0.2), 0.2, tolerance = 1e-5)
})

test_that("get_data", {
  expect_equal(nrow(get_data(m1)), 7)
  expect_equal(colnames(get_data(m1)), c("durable", "age", "quant"))
})

test_that("find_formula", {
  expect_length(find_formula(m1), 1)
  expect_equal(
    find_formula(m1),
    list(conditional = as.formula("durable ~ age + quant")),
    ignore_attr = TRUE
  )
})

test_that("find_terms", {
  expect_equal(find_terms(m1), list(
    response = "durable",
    conditional = c("age", "quant")
  ))
  expect_equal(find_terms(m1, flatten = TRUE), c("durable", "age", "quant"))
})

test_that("n_obs", {
  expect_equal(n_obs(m1), 7)
})

test_that("linkfun", {
  expect_false(is.null(link_function(m1)))
})

test_that("find_parameters", {
  expect_equal(
    find_parameters(m1),
    list(conditional = c(
      "(Intercept)", "age", "quant", "sigma"
    ))
  )
  expect_equal(nrow(get_parameters(m1)), 4)
  expect_equal(
    get_parameters(m1)$Parameter,
    c("(Intercept)", "age", "quant", "sigma")
  )
})

test_that("find_statistic", {
  expect_identical(find_statistic(m1), "t-statistic")
})