test_that("generate.data outputs correct dimensions based on theoretical matrix design", {
  n_samples <- 150
  p_covariates <- 8
  
  dat <- generate.data(n = n_samples, p = p_covariates)
  
  expect_equal(nrow(dat$X), n_samples)
  expect_equal(ncol(dat$X), p_covariates)
  
  expect_equal(length(dat$true.beta), p_covariates)
  
  expect_equal(length(dat$y), n_samples)
  expect_equal(length(dat$A), n_samples)
})

test_that("simml model fitting returns a valid gam object", {
  dat <- generate.data(n = 100, p = 5)
  model <- simml(y = dat$y, A = dat$A, X = dat$X)
  
  expect_true(!is.null(model$g.fit))
  expect_s3_class(model$g.fit, "gam")
  expect_equal(length(model$beta.coef), 5)
})