improve tests and error message

Author: nikosbosse

NAMESPACE

@@ -146,6 +146,7 @@ importFrom(cli,cli_inform)
 importFrom(cli,cli_text)
 importFrom(cli,cli_warn)
 importFrom(cli,col_blue)
+importFrom(cli,qty)
 importFrom(data.table,"%like%")
 importFrom(data.table,':=')
 importFrom(data.table,.I)

R/class-forecast-sample-multivariate.R

@@ -82,6 +82,7 @@ define_grouping_cols <- function(data, across) {
 
 #' @export
 #' @rdname assert_forecast
+#' @importFrom cli cli_abort qty
 #' @keywords validate-forecast-object
 assert_forecast.forecast_sample_multivariate <- function(
   forecast, forecast_type = NULL, verbose = TRUE, ...
@@ -105,8 +106,9 @@ assert_forecast.forecast_sample_multivariate <- function(
     # nolint start: object_usage_linter
     problematic_groups <- group_variations[.scoringutils_N > 1, .scoringutils_group_id]
     cli_abort(
-      "Found groups with inconsistent sample lengths.
-      Groups {.val {problematic_groups}} have different numbers of samples."
+      "Found the following {qty(length(problematic_groups))} group{?s} with an
+      inconsistent sample length, compared to other groups:
+      {.val {problematic_groups}}"
     )
     # nolint end
   }

tests/testthat/test-class-forecast-sample-multivariate.R

@@ -158,11 +158,16 @@ test_that("as_forecast_sample_multivariate() handles errors appropriately", {
     "All forecasts \\(as defined by the forecast unit\\) in a group must have the same number of samples"
   )
 
-  # Test with invalid grouping columns
+  # Test with inconsistent sample lengths after forecast object creation
+  expect_warning(
+    example_sample_multivariate[-(1000:1010), ],
+    "Found the following group with an inconsistent sample length"
+  )
+
+   # Test with invalid grouping columns
   expect_error(
     as_forecast_sample_multivariate(data,
       grouping = c("nonexistent_column")),
     "Must be a subset of"
   )
 })
-