Fixed phpunit tests for postgres

src/Controller/ProjectController.php

@@ -207,6 +207,11 @@ class ProjectController extends AbstractController
         //Preset the BOM entries with the selected parts, when the form was not submitted yet
         $preset_data = new ArrayCollection();
         foreach (explode(',', (string) $request->get('parts', '')) as $part_id) {
+            //Skip empty part IDs. Postgres seems to be especially sensitive to empty strings, as it does not allow them in integer columns
+            if ($part_id === '') {
+                continue;
+            }
+
             $part = $entityManager->getRepository(Part::class)->find($part_id);
             if (null !== $part) {
                 //If there is already a BOM entry for this part, we use this one (we edit it then)

src/Repository/DBElementRepository.php

@@ -79,7 +79,7 @@ class DBElementRepository extends EntityRepository
 
     /**
      * Find all elements that match a list of IDs.
-     *
+     * They are ordered by IDs in an ascending order.
      * @return AbstractDBElement[]
      * @phpstan-return list<TEntityClass>
      */
@@ -89,6 +89,7 @@ class DBElementRepository extends EntityRepository
         $q = $qb->select('element')
             ->where('element.id IN (?1)')
             ->setParameter(1, $ids)
+            ->orderBy('element.id', 'ASC')
             ->getQuery();
 
         return $q->getResult();