tests/testthat/test_diagnostics.R

In IGPFrailty: Inverse Gaussian Process Degradation Models with Frailty

test_that("Anderson-Darling and Likelihood Ratio tests work", {
  data(laser)
  fit_none <- igp_fit(laser, time_col = "t", deg_col = "increase", unit_col = "unit", frailty = "none")
  fit_gamma <- igp_fit(laser, time_col = "t", deg_col = "increase", unit_col = "unit", frailty = "gamma")
  
  # AD test
  u_list <- fit_none$unit_data
  dy <- unlist(lapply(u_list, function(u) u$dy))
  dg <- unlist(lapply(u_list, function(u) 2.0379 * u$dt))
  ad <- ad_test_ig(dy, dg, eta = 13.147)
  expect_s3_class(ad, "ad_test_ig")
  expect_true(ad$statistic > 0)
  expect_true(ad$p_value > 0.05)
  
  # LRT
  lrt <- lr_test(fit_none, fit_gamma)
  expect_s3_class(lrt, "lr_test")
  expect_equal(lrt$df, 1)
  expect_true(lrt$statistic > 0)
  expect_true(lrt$p_value < 0.001)
})