test_that("longitrees returns correct class", {
  data(ltreedata)

  res <- longitrees(y ~ ., time = "time", random = "subject",
                       weight = 0.2, data = ltreedata, gamma = 1.5,
                       bootsize = 30, mins = 40)

  expect_s3_class(res, "longitrees")
})

test_that("threetrees returns correct class", {
  pdf(NULL)
  on.exit(dev.off(), add = TRUE)
  data(ltreedata)

  res <- longitrees(y ~ ., time = "time", random = "subject",
                       weight = 0.2, data = ltreedata, gamma = 1.5,
                       bootsize = 30, mins = 40)
  sel <- selectionplot(res, metric = "PE", nth = 1)
  tt <- threetrees(res, selection = sel)

  expect_s3_class(tt, "threetrees")
  expect_output(summary(tt))
  expect_output(print(tt))
})

test_that("predict.threetrees returns data frame", {
  pdf(NULL)
  on.exit(dev.off(), add = TRUE)
  data(ltreedata)

  res <- longitrees(y ~ ., time = "time", random = "subject",
                       weight = 0.2, data = ltreedata, gamma = 1.5,
                       bootsize = 30, mins = 40)
  sel <- selectionplot(res, metric = "PE", nth = 1)
  tt <- threetrees(res, selection = sel)

  pred <- predict(tt, tree = 1)
  expect_true(is.data.frame(pred))
})

test_that("predict.threetrees errors on invalid tree", {
  dummy <- structure(list(), class = "threetrees")
  expect_error(predict(dummy, tree = 5), "tree must be 1, 2, or 3")
})