test: add warm start test on GR4J

Refs #78

tests/testthat/test-CreateRunOptions.R

+context("CreateRunOptions")
+
+test_that("Warm start of GR4J should give same result as warmed model", {
+  data(L0123001)
+  InputsModel <- CreateInputsModel(FUN_MOD = RunModel_GR4J, DatesR = BasinObs$DatesR, 
+                                   Precip = BasinObs$P, PotEvap = BasinObs$E)
+  Param <- c(X1 = 257.238, X2 = 1.012, X3 = 88.235, X4 = 2.208)
+  Ind_Run1 <- seq(which(format(BasinObs$DatesR, format = "%Y-%m-%d")=="1990-01-01"), 
+                 which(format(BasinObs$DatesR, format = "%Y-%m-%d")=="1990-12-31"))
+  Ind_Run2 <- seq(which(format(BasinObs$DatesR, format = "%Y-%m-%d")=="1991-01-01"), 
+                  which(format(BasinObs$DatesR, format = "%Y-%m-%d")=="1991-12-31"))
+  # 1990-1991
+  RunOptions <- suppressWarnings(CreateRunOptions(FUN_MOD = RunModel_GR4J,
+                                 InputsModel = InputsModel, IndPeriod_Run = c(Ind_Run1, Ind_Run2)))
+  OutputsModel <- RunModel_GR4J(InputsModel = InputsModel,
+                                RunOptions = RunOptions, Param = Param)
+  # 1990
+  RunOptions1 <- suppressWarnings(CreateRunOptions(FUN_MOD = RunModel_GR4J,
+                                 InputsModel = InputsModel, IndPeriod_Run = Ind_Run1))
+  OutputsModel1 <- RunModel_GR4J(InputsModel = InputsModel,
+                                RunOptions = RunOptions1, Param = Param)
+  # Warm start 1991
+  RunOptions2 <- CreateRunOptions(FUN_MOD = RunModel_GR4J,
+                                  InputsModel = InputsModel, IndPeriod_Run = Ind_Run2, 
+                                  IndPeriod_WarmUp = 0L,
+                                  IniStates = OutputsModel1$StateEnd)
+  OutputsModel2 <- RunModel_GR4J(InputsModel = InputsModel,
+                                 RunOptions = RunOptions2, Param = Param)
+  # Compare 1991 Qsim from warm started and from 1990-1991
+  expect_equal(OutputsModel2$Qsim, OutputsModel$Qsim[366:730])
+})