fullmodel <- lm(y ~ x1 + x2 + x3 + x4, data = cement)

test_that("aic output matches expected result", {
  expect_equal(ols_aic(fullmodel, method = "R"), AIC(fullmodel))
  expect_equal(ols_aic(fullmodel, method = "STATA"), 63.83669)
  expect_equal(round(ols_aic(fullmodel, method = "SAS"), 3), 26.944)
  expect_equal(round(ols_aic(fullmodel, method = "SAS", TRUE), 3), 55.944)

  model <- lm(y ~ x1 + x2 + x4, data = cement)
  expect_equal(ols_aic(model, method = "R"), AIC(model))
  expect_equal(round(ols_aic(model, method = "STATA"), 4), 61.8663)

  model <- lm(y ~ x2 + x4, data = cement)
  expect_equal(ols_aic(model, method = "R"), AIC(model))
  expect_equal(round(ols_aic(model, method = "STATA"), 4), 97.5217)
})


test_that("sbc output matches expected result", {
  expect_equal(ols_sbc(fullmodel, method = "R"), BIC(fullmodel))
  expect_equal(round(ols_sbc(fullmodel, method = "STATA"), 4), 66.6614)
  expect_equal(round(ols_sbc(fullmodel, method = "SAS"), 4), 29.769)

  model <- lm(y ~ x1 + x2 + x4, data = cement)
  expect_equal(ols_sbc(model, method = "R"), BIC(model))
  expect_equal(round(ols_sbc(model, method = "STATA"), 4), 64.1261)

  model <- lm(y ~ x2 + x4, data = cement)
  expect_equal(ols_sbc(model, method = "R"), BIC(model))
  expect_equal(round(ols_sbc(model, method = "STATA"), 4), 99.2166)
})

test_that("apc output matches expected result", {
  expect_equal(round(ols_apc(fullmodel), 3), 0.04)

  model <- lm(y ~ x1, data = cement)
  expect_equal(round(ols_apc(model), 3), 0.636)

  model <- lm(y ~ x4, data = cement)
  expect_equal(round(ols_apc(model), 3), 0.444)

  model <- lm(y ~ x1 + x2 + x4, data = cement)
  expect_equal(round(ols_apc(model), 3), 0.033)

  model <- lm(y ~ x1 + x3 + x4, data = cement)
  expect_equal(round(ols_apc(model), 3), 0.035)

  model <- lm(y ~ x2 + x4, data = cement)
  expect_equal(round(ols_apc(model), 3), 0.512)
})


test_that("mallow's cp output matches expected result", {
  model <- lm(y ~ x1, data = cement)
  act <- round(ols_mallows_cp(model, fullmodel), 2)
  exp <- 202.55
  expect_equal(act, exp)

  model <- lm(y ~ x4, data = cement)
  act <- round(ols_mallows_cp(model, fullmodel), 2)
  exp <- 138.73
  expect_equal(act, exp)

  model <- lm(y ~ x1 + x2, data = cement)
  act <- round(ols_mallows_cp(model, fullmodel), 2)
  exp <- 2.68
  expect_equal(act, exp)

  model <- lm(y ~ x2 + x4, data = cement)
  act <- round(ols_mallows_cp(model, fullmodel), 2)
  exp <- 138.23
  expect_equal(act, exp)

  model <- lm(y ~ x1 + x2 + x4, data = cement)
  act <- round(ols_mallows_cp(model, fullmodel), 2)
  exp <- 3.02
  expect_equal(act, exp)

  model <- lm(y ~ x1 + x3 + x4, data = cement)
  act <- round(ols_mallows_cp(model, fullmodel), 2)
  exp <- 3.50
  expect_equal(act, exp)
})