skip_if_not_installed("survey")

data(api, package = "survey")
dstrat <-
  survey::svydesign(
    id = ~1,
    strata = ~stype,
    weights = ~pw,
    data = apistrat,
    fpc = ~fpc
  )

m1 <- survey::svyglm(api00 ~ ell + meals + mobility, design = dstrat)

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

test_that("find_predictors", {
  expect_identical(find_predictors(m1), list(conditional = c("ell", "meals", "mobility")))
  expect_null(find_predictors(m1, effects = "random"))
})

test_that("find_response", {
  expect_identical(find_response(m1), "api00")
})

test_that("get_response", {
  expect_equal(get_response(m1), apistrat$api00)
})

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, verbose = FALSE)), 200)
  expect_equal(
    colnames(get_data(m1, verbose = FALSE)),
    c("api00", "ell", "meals", "mobility", "(weights)")
  )
})

test_that("find_formula", {
  expect_length(find_formula(m1), 1)
  expect_equal(
    find_formula(m1),
    list(conditional = as.formula("api00 ~ ell + meals + mobility")),
    ignore_attr = TRUE
  )
})

test_that("find_terms", {
  expect_equal(find_terms(m1), list(
    response = "api00",
    conditional = c("ell", "meals", "mobility")
  ))
  expect_equal(
    find_terms(m1, flatten = TRUE),
    c("api00", "ell", "meals", "mobility")
  )
})

test_that("n_obs", {
  expect_equal(n_obs(m1), 200)
})

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

test_that("find_parameters", {
  expect_equal(
    find_parameters(m1),
    list(conditional = c(
      "(Intercept)", "ell", "meals", "mobility"
    ))
  )
  expect_equal(nrow(get_parameters(m1)), 4)
  expect_equal(
    get_parameters(m1)$Parameter,
    c("(Intercept)", "ell", "meals", "mobility")
  )
})

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