test_that("supplementary_add() returns correct values", {
  # Check against The Eurostat Manual page 494
  de_io <- iotable_get()


  CO2_coefficients <- data.frame(
    agriculture_group = 0.2379,
    industry_group = 0.5172,
    construction = 0.0456,
    trade_group = 0.1320,
    business_services_group = 0.0127,
    other_services_group = 0.0530
  )

  CH4_coefficients <- data.frame(
    agriculture_group = 0.0349,
    industry_group = 0.0011,
    construction = 0,
    trade_group = 0,
    business_services_group = 0,
    other_services_group = 0.0021
  )
  CO2 <- cbind(
    data.frame(iotables_row = "CO2_coefficients"),
    CO2_coefficients
  )

  CH4 <- cbind(
    data.frame(iotables_row = "CH4_coefficients"),
    CH4_coefficients
  )

  de_coeff <- input_coefficient_matrix_create(iotable_get())

  emissions <- rbind(CO2, CH4)
  supplementary_data <- emissions

  extended <- supplementary_add(
    data_table = de_io,
    supplementary_data = emissions
  )
  expect_equal(extended$construction[which(extended[, 1] == "CO2_coefficients")],
    0.0456,
    tolerance = 1e-6
  )
  expect_equal(extended$other_services_group[which(extended[, 1] == "CO2_coefficients")],
    0.0530,
    tolerance = 1e-6
  )
  expect_equal(extended$other_services_group[which(extended[, 1] == "CH4_coefficients")],
    0.0021,
    tolerance = 1e-6
  )
})