fix tests

Author: Vlad0n20

api/providers/serializers.py

@@ -126,6 +126,11 @@ class Meta:
         related_view_kwargs={'brand_id': '<brand.id>'},
     )
 
+    required_metadata_template = RelationshipField(
+        related_view='cedar-metadata-templates:cedar-metadata-template-detail',
+        related_view_kwargs={'template_id': '<required_metadata_template._id>'},
+        read_only=True,
+    )
     filterable_fields = frozenset([
         'allow_submissions',
         'allow_commenting',
@@ -193,6 +198,11 @@ class Meta:
         related_view_kwargs={'provider_id': '<_id>'},
     )
 
+    required_metadata_template = RelationshipField(
+        related_view='cedar-metadata-templates:cedar-metadata-template-detail',
+        related_view_kwargs={'template_id': '<required_metadata_template._id>'},
+    )
+
     links = LinksField({
         'self': 'get_absolute_url',
         'external_url': 'get_external_url',
@@ -263,6 +273,11 @@ class Meta:
         related_view_kwargs={'brand_id': '<brand.id>'},
     )
 
+    required_metadata_template = RelationshipField(
+        related_view='cedar-metadata-templates:cedar-metadata-template-detail',
+        related_view_kwargs={'template_id': '<required_metadata_template._id>'},
+    )
+
     def get_preprints_url(self, obj):
         return absolute_reverse(
             'providers:preprint-providers:preprints-list', kwargs={