add test to test_preprint_detail.py

api_tests/preprints/views/test_preprint_detail.py

@@ -1,6 +1,6 @@
 import pytest
 from django.utils import timezone
-from osf_tests.factories import PreprintFactory, AuthUserFactory, ProjectFactory
+from osf_tests.factories import PreprintFactory, AuthUserFactory, ProjectFactory, InstitutionFactory
 from api.base.settings.defaults import API_BASE
 from website.settings import DOI_FORMAT
 
@@ -45,6 +45,10 @@ def res(self, app, url):
     def data(self, res):
         return res.json['data']
 
+    @pytest.fixture()
+    def institution(self, res):
+        return InstitutionFactory()
+
     def test_preprint_detail(self, app, user, preprint, url, res, data):
         assert res.status_code == 200
         assert res.content_type == 'application/vnd.api+json'
@@ -139,3 +143,13 @@ def test_preprint_embed_identifiers(self, app, user, preprint, url):
         assert res.status_code == 200
         link = res.json['data']['relationships']['identifiers']['links']['related']['href']
         assert f'{url}identifiers/' in link
+
+    def test_return_affiliated_institutions(self, app, user, preprint,  institution, url):
+        """
+        Confirmation test for the the new preprint affiliated institutions feature
+        """
+        preprint.affiliated_institutions.add(institution)
+        res = app.get(url)
+        assert res.status_code == 200
+        relationship_link = res.json['data']['relationships']['affiliated_institutions']['links']['related']['href']
+        assert f'/v2/preprints/{preprint._id}/institutions/' in relationship_link