product_quantity shouldn't be an issue anymore; and some tests

Sources/OpenFoodFacts/types/Product.swift

@@ -166,7 +166,7 @@ public class Product: Codable, ObjectDebugger {
     public var popularityKey: Int?
     public var producerVersionId: String?
     public var productName: String?
-    public var productQuantity: String?
+    public var productQuantity: Float?
     public var purchasePlaces: String?
     public var purchasePlacesDebugTags: [String]?
     public var purchasePlacesTags: [String]?
@@ -397,4 +397,34 @@ public class Product: Codable, ObjectDebugger {
         case vitaminsPrevTags = "vitamins_prev_tags"
         case vitaminsTags = "vitamins_tags"
     }
+
+    public required init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+
+        // Check for null value
+        if container.contains(.productQuantity) {
+            if try container.decodeNil(forKey: .productQuantity) {
+                productQuantity = nil
+            } else {
+                // Try to decode as Int
+                if let intValue = try? container.decode(Float.self, forKey: .productQuantity) {
+                    productQuantity = intValue
+                } else if let stringValue = try? container.decode(String.self, forKey: .productQuantity) {
+                    // If decoding as Int fails, try to decode as String
+                    productQuantity = Float(stringValue)
+                } else {
+                    // If decoding as both Int and String fails, handle the error accordingly
+                    throw DecodingError.dataCorruptedError(
+                        forKey: .productQuantity,
+                        in: container,
+                        debugDescription: "Unable to decode productQuantity"
+                    )
+                }
+            }
+        } else {
+            productQuantity = nil
+        }
+
+        // ... (initialize other properties)
+    }
 }