test_that("estimate_gps works as expected.", {

  skip_on_cran()
  set.seed(895)
  data.table::setDTthreads(1)
  m_d <- generate_syn_data(sample_size = 100)
  m_d$id <- seq_along(1:nrow(m_d))

  data_with_gps_1 <- estimate_gps(m_d[, c("id", "w")],
                                  m_d[, c("id", "cf1", "cf2", "cf3",
                                          "cf4", "cf5", "cf6")],
                                  sl_lib = c("m_xgboost"))

  expect_equal(length(data_with_gps_1$dataset), 6)
  expect_equal(nrow(data_with_gps_1$dataset), 100)
  expect_equal(data_with_gps_1$dataset$gps[2], 20.991916, tolerance = 0.00001)
  expect_true(any(colnames(data_with_gps_1$dataset) %in% "id"))

  data_with_gps_2 <- estimate_gps(m_d[, c("id", "w")],
                                  m_d[, c("id", "cf1", "cf2", "cf3",
                                          "cf4", "cf5", "cf6")],
                                  sl_lib = c("m_xgboost")
  )

  required_elements <- c( "dataset",
                          "gps_mx",
                          "w_mx" )
  expect_equal(length(intersect(c(attributes(data_with_gps_2)$names),
                                required_elements)), 3L)
  expect_equal(data_with_gps_2$dataset$e_gps_pred[58,], 19.07269287,
               tolerance = 0.00001)

  # Missing values
  set.seed(1789)
  m_d_2 <- generate_syn_data(sample_size = 100)
  m_d_2$w[20] <- NA
  m_d_2$id <- seq_along(1:nrow(m_d_2))
  # Missing value in target
  # Error because SL does not support missing data.
  expect_error(estimate_gps(m_d_2[, c("id", "w")],
                            m_d_2[, c("id", "w")],
                            m_d_3[c("cf1","cf2","cf3","cf4","cf5","cf6")],
                            pred_model = "sl",
                            sl_lib = c("m_xgboost"))
               )

})


test_that("estimate_gps merges data correctly.", {
  skip_on_cran()
  set.seed(895)
  m_d <- generate_syn_data(sample_size = 1000)
  m_d$id <- seq_along(1:nrow(m_d))

  # change some of ids
  m_d_2 <- m_d
  m_d_2[sample(1:nrow(m_d_2), 400), c("id")] <- 1000000

  data_with_gps_1 <- estimate_gps(m_d[, c("id", "w")],
                                  m_d_2[, c("id", "cf1", "cf2", "cf3",
                                            "cf4", "cf5", "cf6")],
                                  sl_lib = c("m_xgboost")
  )

  expect_equal(nrow(data_with_gps_1$dataset), 600)

})

test_that("estimate_gps input data should include id column.", {
  skip_on_cran()
  set.seed(895)
  m_d <- generate_syn_data(sample_size = 1000)
  m_d$id <- seq_along(1:nrow(m_d))

  expect_error(estimate_gps(m_d[, c("w")],
                            m_d[, c("id", "cf1", "cf2", "cf3",
                                    "cf4", "cf5", "cf6")],
                            sl_lib = c("m_xgboost")),
               regexp = "w should include id column.")

  expect_error(estimate_gps(m_d[, c("id", "w")],
                            m_d[, c("cf1", "cf2", "cf3",
                                    "cf4", "cf5", "cf6")],
                            sl_lib = c("m_xgboost")),
               regexp = "c should include id column.")


})


test_that("estimate_gps residuals works as expected.", {
  skip_on_cran()
  set.seed(895)
  m_d <- generate_syn_data(sample_size = 1000)
  data_with_gps <- estimate_gps(m_d[, c("id", "w")],
                                m_d[, c("id", "cf1", "cf2", "cf3",
                                        "cf4", "cf5", "cf6")],
                                sl_lib = c("m_xgboost"),
                                params = list(xgb_max_depth = c(3,4,5),
                                              xgb_rounds = c(10,20,30,40)),
                                gps_density = "normal")
  std_pred <- data_with_gps$dataset$e_gps_std_pred
  expect_equal(std_pred[2], std_pred[30], tolerance = 0.0000001)
  expect_equal(std_pred[200], std_pred[650], tolerance = 0.0000001)


  set.seed(274)
  m_d <- generate_syn_data(sample_size = 1000)
  data_with_gps <- estimate_gps(m_d[, c("id", "w")],
                                m_d[, c("id", "cf1", "cf2", "cf3",
                                        "cf4", "cf5", "cf6")],
                                sl_lib = c("m_xgboost"),
                                params = list(xgb_max_depth = c(3,4,5),
                                              xgb_rounds = c(10,20,30,40)),
                                gps_density = "kernel")
  std_pred <- data_with_gps$dataset$e_gps_std_pred
  expect_true(std_pred[2] != std_pred[30])
  expect_true(std_pred[200] != std_pred[650])
})


test_that("estimate_gps works as expected for non-overlapped ids.", {
  skip_on_cran()
  set.seed(895)
  m_d <- generate_syn_data(sample_size = 1000)
  m_d_2 <- m_d
  m_d_2$id <- m_d_2$id + 10000

  expect_error(estimate_gps(m_d[, c("id", "w")],
                            m_d_2[, c("id", "cf1", "cf2", "cf3",
                                      "cf4", "cf5", "cf6")],
                            sl_lib = c("m_xgboost"),
                            params = list(xgb_max_depth = c(3,4,5),
                                              xgb_rounds = c(10,20,30,40)),
                                gps_density = "normal"),
    regexp = paste0("Merged data length is 0.",
                    " Make sure that w and c belong to the same observations, ",
                    " or partially include same observations."))
})