tests/testthat/test_frailty.R

In IGPFrailty: Inverse Gaussian Process Degradation Models with Frailty

test_that("individual_frailty computes posterior expectations and variances", {
  data(laser)
  fit_gam <- igp_fit(laser, time_col = "t", deg_col = "increase", unit_col = "unit", frailty = "gamma")
  
  frail <- individual_frailty(fit_gam)
  expect_s3_class(frail, "individual_frailty")
  expect_equal(nrow(frail$estimates), 15)
  expect_true(all(frail$estimates$E_z > 0))
  expect_true(all(frail$estimates$Var_z >= 0))
  
  # Unit 10 is most fragile in Laser data
  expect_equal(as.character(frail$estimates$unit[frail$estimates$fragility_rank == 1]), "10")
  expect_equal(unname(round(frail$estimates$E_z[frail$estimates$unit == "10"], 3)), 1.948)
  
  # Errors on classical IGP
  fit_none <- igp_fit(laser, time_col = "t", deg_col = "increase", unit_col = "unit", frailty = "none")
  expect_error(individual_frailty(fit_none), "cannot be estimated")
})