diff --git a/src/Bundle/ChillPersonBundle/Entity/Relationships/Relationship.php b/src/Bundle/ChillPersonBundle/Entity/Relationships/Relationship.php
index f736913ae..ce56fa013 100644
--- a/src/Bundle/ChillPersonBundle/Entity/Relationships/Relationship.php
+++ b/src/Bundle/ChillPersonBundle/Entity/Relationships/Relationship.php
@@ -147,10 +147,16 @@ class Relationship implements TrackCreationInterface, TrackUpdateInterface
     public function getOpposite(Person $counterpart): Person
     {
         if ($this->fromPerson !== $counterpart && $this->toPerson !== $counterpart) {
-            throw new \RuntimeException('the counterpart is neither the from nor to person for this relationship');
+            // during tests, comparing using equality does not work. We have to compare the ids
+            if (
+                ($this->fromPerson->getId() === $counterpart->getId() && $this->toPerson->getId() === $counterpart->getId())
+                || null === $counterpart->getId()
+            ) {
+                throw new \RuntimeException(sprintf('the counterpart is neither the from nor to person for this relationship, expecting counterpart from %d and available %d and %d', $counterpart->getId(), $this->getFromPerson()->getId(), $this->getToPerson()->getId()));
+            }
         }
 
-        if ($this->fromPerson === $counterpart) {
+        if ($this->fromPerson === $counterpart || $this->fromPerson->getId() === $counterpart->getId()) {
             return $this->toPerson;
         }