.runThisTest <- Sys.getenv("RunAllggeffectsTests") == "yes"

if (.runThisTest) {
  unloadNamespace("gam")

  if (requiet("testthat") && requiet("ggeffects") && requiet("gamm4")) {

    set.seed(123)
    dat <- gamSim(1, n = 400, scale = 2) ## simulate 4 term additive truth
    dat$fac <- fac <- as.factor(sample(1:20, 400, replace = TRUE))
    dat$y <- dat$y + model.matrix( ~ fac - 1) %*% rnorm(20) * .5

    set.seed(123)
    m1 <- gamm4(y ~ s(x0) + x1 + s(x2), data = dat, random =  ~ (1 | fac))

    test_that("ggpredict", {
      p <- ggpredict(m1, "x1")
      expect_equal(p$predicted[1], 5.885441, tolerance = 1e-4)
      expect_s3_class(ggpredict(m1, c("x1", "x2")), "data.frame")
    })

  }
}