UPDATE: Add test to check that the Fortran version works

tests/testthat/test-evap.R

+context("Test evaporation")
+
+test_that("PEdaily_Oudin works", {
+  skip_on_cran()
+  rm(list = ls())
+  
+  data(L0123001)
+  PotEvap <- PEdaily_Oudin(JD = as.POSIXlt(BasinObs$DatesR)$yday + 1,
+                           Temp = BasinObs$T,
+                           Lat = 0.8, LatUnit = "rad")
+  PotEvapFor <- PEdaily_Oudin(JD = as.POSIXlt(BasinObs$DatesR)$yday + 1,
+                              Temp = BasinObs$T,
+                              Lat = 0.8, LatUnit = "rad", run_fortran = T)
+  expect_true(all(range(PotEvap - PotEvapFor) < 0.001))
+})