Running examples in ‘Covid19Wastewater-Ex.R’ failed
The error most likely occurred in:

> ### Name: OffsetHeatmap
> ### Title: Outputs a heatmap of the offset for variant / time windows and
> ###   population size / region
> ### Aliases: OffsetHeatmap
> 
> ### ** Examples
> 
> data(WasteWater_data, package = "Covid19Wastewater")
> data("Case_data", package = "Covid19Wastewater")
> data(Pop_data, package = "Covid19Wastewater")
> covarstarts <- c(as.Date("2020-08-17"),
+                  as.Date("2021-03-29"))
> covarends <- c(as.Date("2021-01-18"),
+                as.Date("2021-05-24"))
> covarnames <- c("Robin1",
+                 "Alpha.V1")
> OffsetHeatmap("kendall_offset", 0, WasteWater_data, Case_data, Pop_data,
+                covarstarts, covarends, covarnames, "pop", TRUE, TRUE)
Joining with `by = join_by(site)`
Joining with `by = join_by(time)`
Error in `geom_rect()`:
! Problem while computing aesthetics.
ℹ Error occurred in the 1st layer.
Caused by error in `as.Date.numeric()`:
! 'origin' must be supplied
Backtrace:
     ▆
  1. ├─base (local) `<fn>`(x)
  2. ├─ggplot2:::print.ggplot(x)
  3. │ ├─ggplot2::ggplot_build(x)
  4. │ └─ggplot2:::ggplot_build.ggplot(x)
  5. │   └─ggplot2:::by_layer(...)
  6. │     ├─rlang::try_fetch(...)
  7. │     │ ├─base::tryCatch(...)
  8. │     │ │ └─base (local) tryCatchList(expr, classes, parentenv, handlers)
  9. │     │ │   └─base (local) tryCatchOne(expr, names, parentenv, handlers[[1L]])
 10. │     │ │     └─base (local) doTryCatch(return(expr), name, parentenv, handler)
 11. │     │ └─base::withCallingHandlers(...)
 12. │     └─ggplot2 (local) f(l = layers[[i]], d = data[[i]])
 13. │       └─l$compute_aesthetics(d, plot)
 14. │         └─ggplot2 (local) compute_aesthetics(..., self = self)
 15. │           └─ggplot2:::scales_add_defaults(...)
 16. │             └─base::lapply(aesthetics[new_aesthetics], eval_tidy, data = data)
 17. │               └─rlang (local) FUN(X[[i]], ...)
 18. ├─base::as.Date(start + firstday)
 19. ├─base::as.Date.numeric(start + firstday)
 20. │ └─base::stop("'origin' must be supplied")
 21. └─base::.handleSimpleError(...)
 22.   └─rlang (local) h(simpleError(msg, call))
 23.     └─handlers[[1L]](cnd)
 24.       └─cli::cli_abort(...)
 25.         └─rlang::abort(...)
Execution halted