Fix assignment membership query to handle multiple rows per student/role

We store one membership role per assignment, course and role. The
existing query used SQLA .one() while querying by just assignment and
student which would raise one more that one role existed.

Use .first instead and assert the existence of the membership object
below.

The existing assert on  lti_v11_lis_result_sourcedid is there for the
typechecker benefit but we also include that condition on the query

lms/services/lti_grading/_v11.py

@@ -76,12 +76,12 @@ def sync_grade(
             select(LMSUserAssignmentMembership).where(
                 LMSUserAssignmentMembership.lms_user_id == lms_user.id,
                 LMSUserAssignmentMembership.assignment_id == assignment.id,
+                LMSUserAssignmentMembership.lti_v11_lis_result_sourcedid.is_not(None),
             )
-        ).one()
+        ).first()
         assert (
-            assignment_membership.lti_v11_lis_result_sourcedid
-        ), "Trying to grade a student without lti_v11_lis_result_sourcedid"
-
+            assignment_membership and assignment_membership.lti_v11_lis_result_sourcedid
+        ), "Trying to grade a student without a membership or membership without lti_v11_lis_result_sourcedid"
         request = self._record_score_payload(
             score=score,
             user_grading_id=assignment_membership.lti_v11_lis_result_sourcedid,

tests/unit/lms/services/lti_grading/_v11_test.py

@@ -74,23 +74,34 @@ def test_record_result(self, svc, score, http_service, score_payload):
     def test_sync_grade(self, svc, http_service, application_instance, db_session):
         lms_user = factories.LMSUser()
         assignment = factories.Assignment()
-        lti_role = factories.LTIRole()
-        db_session.flush()
-        membership = factories.LMSUserAssignmentMembership(
-            lms_user_id=lms_user.id,
-            assignment_id=assignment.id,
-            lti_role_id=lti_role.id,
+        factories.LMSUserAssignmentMembership(
+            lms_user=lms_user,
+            assignment=assignment,
+            lti_role=factories.LTIRole(),
+            lti_v11_lis_result_sourcedid="LIS",
+        )
+        # Membership for another role
+        factories.LMSUserAssignmentMembership(
+            lms_user=lms_user,
+            assignment=assignment,
+            lti_role=factories.LTIRole(),
             lti_v11_lis_result_sourcedid="LIS",
         )
+        # Membership without lis_result_sourcedid
+        factories.LMSUserAssignmentMembership(
+            lms_user=lms_user,
+            assignment=assignment,
+            lti_role=factories.LTIRole(),
+            lti_v11_lis_result_sourcedid=None,
+        )
+        db_session.flush()
 
         svc.sync_grade(application_instance, assignment, None, lms_user, 0.5)
 
         assert self.sent_pox_body(http_service) == {
             "replaceResultRequest": {
                 "resultRecord": {
-                    "sourcedGUID": {
-                        "sourcedId": membership.lti_v11_lis_result_sourcedid
-                    },
+                    "sourcedGUID": {"sourcedId": "LIS"},
                     "result": {"resultScore": {"language": "en", "textString": "0.5"}},
                 }
             }