test_that("survival model gives informative error when coxme is unavailable", {
  
  testthat::local_mocked_bindings(
    .has_coxme = function() FALSE,
    .package = "BioMixModel"
  )
  
  expect_error(
    fit_survival_mix(
      formula = survival::Surv(time, status) ~ x,
      data = data.frame(
        time = c(1, 2, 3),
        status = c(1, 0, 1),
        x = c(1, 2, 3)
      )
    ),
    "Package 'coxme' is required for survival mixed models."
  )
})