class(pop) (`actual`) not identical to c("gg", "ggplot") (`expected`).

`actual`:        "ggplot2::ggplot" "ggplot" "ggplot2::gg" "S7_object" "gg"    
`expected[2:2]`:                                                      "ggplot"

study_area <- rnaturalearth::ne_countries(scale = 50, continent = "Europe",
po <- LBI(study_area_id = "Sweden", study_area_polygon = study_area,
nobs = 10, nboot = 10, fact_location = 10, elevation = NULL,
test <- as.data.frame(po$all[, c("study_area_id", "distance_km",
pop <- windrose(data = test, spd = "distance_km", dir = "bearing")
windrose(data = test, spd = "distance_km", dir = "bearing",
"spdres must be numeric.", fixed = TRUE)