coef_m <- function() {
  m <- as.matrix(es_coefficients[, -1])
  rownames(m) <- es_coefficients$landuse
  m
}

test_that("ESV totals and changes are correct", {
  a1 <- setNames(landuse_change$area_2005, landuse_change$landuse)
  a2 <- setNames(landuse_change$area_2025, landuse_change$landuse)
  esv <- ecosystem_service_value(a1, coef_m(), area2 = a2)
  expect_equal(esv$total[["period1"]], sum(a1 * coef_m()))
  expect_equal(sum(esv$by_landuse$value), sum(esv$by_service$value))
  expect_equal(sum(esv$by_service$change),
               esv$total[["period2"]] - esv$total[["period1"]])
  # CS equals each land use's share of ESV under proportional adjustment
  expect_equal(esv$sensitivity$cs, esv$by_landuse$value / sum(esv$by_landuse$value))
  expect_output(print(esv), "Total ESV")
})

test_that("ESV input checks", {
  m <- coef_m()
  expect_error(ecosystem_service_value(c(1, 2), m))
  expect_error(ecosystem_service_value(c(mars = 1), m))
  expect_error(ecosystem_service_value(c(cropland = 1), m,
                                       area2 = c(orchard = 1)))
})

test_that("benefit transfer adjusts correctly", {
  bt <- benefit_transfer(100, study_income = 400, policy_income = 100,
                         elasticity = 0.5, price_index_ratio = 1.2,
                         exchange_rate = 0.5, quantity = 10,
                         elasticity_range = c(0, 1), transfer_error = 0.1)
  expect_equal(bt$unit_value, 100 * 0.5 * 1.2 / 0.5)
  expect_equal(bt$total_value, bt$unit_value * 10)
  expect_equal(bt$unit_low, 100 * 0.25 * 1.2 / 0.5 * 0.9)
  expect_equal(bt$unit_high, 100 * 1 * 1.2 / 0.5 * 1.1)
  expect_equal(nrow(benefit_transfer(c(1, 2, 3), 1, 1)), 3)
  expect_error(benefit_transfer(1, 0, 1))
})