FactoryGirl\Provider\Doctrine\FixtureFactory::setField PHP Method

    protected function setField($ent, EntityDef $def, $fieldName, $fieldValue)
    {
        $metadata = $def->getEntityMetadata();
        if ($metadata->isCollectionValuedAssociation($fieldName)) {
            $metadata->setFieldValue($ent, $fieldName, $this->createCollectionFrom($fieldValue));
        } else {
            $metadata->setFieldValue($ent, $fieldName, $fieldValue);
            if (is_object($fieldValue) && $metadata->isSingleValuedAssociation($fieldName)) {
                $this->updateCollectionSideOfAssocation($ent, $metadata, $fieldName, $fieldValue);
            }
        }
    }