refactor: ♻️ add contained_doses variable to output (#187)

## Description

As per the documentation update, this adds the variable
`contained_doses` from the multiplication of volume and apk

Will not build correctly, since it depends on #185

## Checklist

- [x] Ran `just run-all`

R/include-gld-purchases.R

@@ -20,14 +20,19 @@ include_gld_purchases <- function(lmdb) {
     column_names_to_lower() |>
     # Use !! to inject the expression into filter.
     dplyr::filter(!!criteria) |>
+    dplyr::mutate(
+      contained_doses = .data$volume * .data$apk,
+      # An indicator variable for later joins
+      has_gld_purchases = TRUE
+    ) |>
     # Keep only the columns we need.
     dplyr::select(
       "pnr",
       # Change to date to work with later functions.
       date = "eksd",
       "atc",
-      "volume",
-      "apk",
-      "indo"
+      "contained_doses",
+      "has_gld_purchases",
+      indication_code = "indo"
     )
 }

tests/testthat/test-include-gld-purchases.R

@@ -24,8 +24,13 @@ expected <- tibble::tribble(
   "A10123",
 ) |>
   dplyr::bind_cols(constants) |>
-  dplyr::rename(date = eksd) |>
-  dplyr::relocate(atc, .after = date)
+  dplyr::rename(date = eksd, indication_code = indo) |>
+  dplyr::mutate(
+    contained_doses = volume * apk,
+    has_gld_purchases = TRUE
+  ) |>
+  dplyr::select(-volume, -apk) |>
+  dplyr::relocate(pnr, date, atc, contained_doses, has_gld_purchases, indication_code)
 
 test_that("dataset needs expected variables", {
   actual <- lmdb[-2]