feat: check postprocessor for forecast_date in forecast.epi_workflow

Author: dshemetov

R/epi_workflow.R

@@ -360,12 +360,17 @@ forecast.epi_workflow <- function(object, ..., fill_locf = FALSE, n_recent = NUL
     ))
   }
 
+  frosting_fd <- NULL
+  if (has_postprocessor(object) && detect_layer(object, "layer_add_forecast_date")) {
+    frosting_fd <- extract_argument(object, "layer_add_forecast_date", "forecast_date")
+  }
+
   test_data <- get_test_data(
     hardhat::extract_preprocessor(object),
     object$original_data,
     fill_locf = fill_locf,
     n_recent = n_recent %||% Inf,
-    forecast_date = forecast_date %||% max(object$original_data$time_value)
+    forecast_date = forecast_date %||% frosting_fd %||% max(object$original_data$time_value)
   )
 
   predict(object, new_data = test_data)