Fixing infinite loop in benchmarks

A customer could buy a product more than one time, which generated two
identical entries in the `products_available_to_rate` collection. When
it was a vec and the rng-generated number of reviews was requested such
that all the unique reviewable products were reviewed, the previous code
would sit in an infinite loop due to the number of ratings being less
than the number of available products to rate.

By changing the collection to a HashSet, we have to update the code that
searched for an entry, but we fix the underlying issue of trying to
generate too many reviews. We also make the performance of the faking a
bit more predictable, since the generated random number can't "miss"
anymore. The next available entry will be used.

benchmarks/benches/commerce/model.rs

@@ -26,6 +26,7 @@ pub struct InitialDataSet {
     pub reviews: Vec<ProductReview>,
 }
 
+#[derive(Debug)]
 pub struct InitialDataSetConfig {
     pub number_of_customers: RangeInclusive<u32>,
     pub number_of_products: RangeInclusive<u32>,
@@ -67,7 +68,7 @@ impl InitialDataSetConfig {
                     .iter()
                     .map(|&product_id| (order.customer_id, product_id))
             })
-            .collect::<Vec<_>>();
+            .collect::<HashSet<_>>();
         let mut rated_products = HashSet::new();
         if !products_available_to_rate.is_empty() {
             for _ in 0..gen_range(rng, self.number_of_reviews.clone()) {
@@ -228,23 +229,32 @@ pub struct ProductReview {
 impl ProductReview {
     pub fn fake<R: Rng>(
         rng: &mut R,
-        available_customer_products: &[(u32, u32)],
+        available_customer_products: &HashSet<(u32, u32)>,
         already_rated: &mut HashSet<(u32, u32)>,
     ) -> Option<Self> {
-        while available_customer_products.len() > already_rated.len() {
-            let index = rng.gen_range(0..available_customer_products.len());
-            let (customer_id, product_id) = available_customer_products[index];
-            if already_rated.insert((customer_id, product_id)) {
-                return Some(Self {
-                    customer_id,
-                    product_id,
-                    rating: rng.gen_range(1..=5),
-                    review: if rng.gen_bool(0.25) {
-                        Some(Vec::<String>::dummy_with_rng(&Paragraphs(EN, 1..5), rng).join("\n\n"))
-                    } else {
-                        None
-                    },
-                });
+        if available_customer_products.len() > already_rated.len() {
+            for (customer_id, product_id) in available_customer_products
+                .iter()
+                .chain(available_customer_products.iter())
+                .skip(rng.gen_range(0..available_customer_products.len()))
+                .take(available_customer_products.len())
+                .copied()
+            {
+                if already_rated.insert((customer_id, product_id)) {
+                    return Some(Self {
+                        customer_id,
+                        product_id,
+                        rating: rng.gen_range(1..=5),
+                        review: if rng.gen_bool(0.25) {
+                            Some(
+                                Vec::<String>::dummy_with_rng(&Paragraphs(EN, 1..5), rng)
+                                    .join("\n\n"),
+                            )
+                        } else {
+                            None
+                        },
+                    });
+                }
             }
         }