HP-1751 tiny

Author: VadymHrechukha

src/product/BillingRegistry.php

@@ -53,6 +53,12 @@ public function getRepresentationsByType(string $representationClass): array
             throw new InvalidRepresentationException("Class '$representationClass' does not exist");
         }
 
+        if (!is_subclass_of($representationClass, RepresentationInterface::class)) {
+            throw new InvalidBehaviorException(
+                sprintf('Representation class "%s" does not implement RepresentationInterface', $representationClass)
+            );
+        }
+
         $representations = [];
         foreach ($this->priceTypes() as $priceTypeDefinition) {
             foreach ($priceTypeDefinition->documentRepresentation() as $representation) {
@@ -100,6 +106,12 @@ public function getBehavior(string $type, string $behaviorClassWrapper): Behavio
             );
         }
 
+        if (!is_subclass_of($behaviorClassWrapper, BehaviorInterface::class)) {
+            throw new InvalidBehaviorException(
+                sprintf('Behavior class "%s" does not implement BehaviorInterface', $behaviorClassWrapper)
+            );
+        }
+
         $billingType = $this->convertStringTypeToType($type);
 
         foreach ($this->priceTypes() as $priceTypeDefinition) {