Always take the lowest price

Author: Jade-GG

src/Models/Product.php

@@ -7,6 +7,7 @@
 use Illuminate\Database\Eloquent\Relations\BelongsToMany;
 use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\Relations\HasOne;
+use Illuminate\Support\Arr;
 use Illuminate\Support\Collection;
 use Rapidez\Core\Facades\Rapidez;
 use Rapidez\Core\Models\Relations\BelongsToManyCallback;
@@ -241,13 +242,9 @@ public function getUnitPrice(int $quantity = 1, int $customerGroup = 0)
         // NOTE: We always need the option with the lowest matching value, *not* the one with the highest matching qty!
         // It wouldn't make sense to select a tier with a higher qty if the price is higher.
 
-        $price = $tierPrice ?? $this->price;
+        $prices = [$tierPrice, $this->price, $this->specialPrice];
 
-        if ($this->specialPrice && $this->specialPrice < $price) {
-            return $this->specialPrice;
-        }
-
-        return $price;
+        return min(Arr::whereNotNull($prices));
     }
 
     public function getPrice(int $quantity = 1, int $customerGroup = 0)

tests/Unit/ProductPriceTest.php

@@ -57,6 +57,7 @@ public function product_can_have_tier_prices()
     {
         $product = Product::find(4);
 
+        $product->tierPrices()->create(['qty' => 2, 'value' => 50, 'website_id' => 1, 'all_groups' => 1, 'customer_group_id' => 0]);
         $product->tierPrices()->create(['qty' => 5, 'value' => 40, 'website_id' => 1, 'all_groups' => 1, 'customer_group_id' => 0]);
         $product->tierPrices()->create(['qty' => 10, 'value' => 35, 'website_id' => 1, 'all_groups' => 1, 'customer_group_id' => 0]);
         $product->tierPrices()->create(['qty' => 15, 'value' => 40, 'website_id' => 1, 'all_groups' => 1, 'customer_group_id' => 0]);