diff --git a/tests/unit/lms/services/assignment_test.py b/tests/unit/lms/services/assignment_test.py
index 71e8aa66c7..5561383c79 100644
--- a/tests/unit/lms/services/assignment_test.py
+++ b/tests/unit/lms/services/assignment_test.py
@@ -4,7 +4,7 @@
 import pytest
 from h_matchers import Any
 
-from lms.models import AssignmentGrouping, AssignmentMembership, RoleScope
+from lms.models import AssignmentGrouping, AssignmentMembership, RoleScope, RoleType
 from lms.services.assignment import AssignmentService, factory
 from tests import factories
 
@@ -239,55 +239,52 @@ def test_is_member(self, svc, db_session):
         assert svc.is_member(assignment, user.h_userid)
         assert not svc.is_member(assignment, other_user.h_userid)
 
-    def test_get_assignments(self, svc, db_session):
-        assert db_session.scalars(svc.get_assignments()).all()
-
-    def test_get_assignments_by_course(self, svc, db_session, assignment):
+    @pytest.mark.parametrize("instructor_h_userid", [True, False])
+    @pytest.mark.parametrize("course_id", [True, False])
+    @pytest.mark.parametrize("h_userids", [True, False])
+    def test_get_assignments(
+        self,
+        svc,
+        db_session,
+        instructor_h_userid,
+        assignment,
+        with_assignment_noise,
+        course_id,
+        h_userids,
+    ):
+        factories.User()
         course = factories.Course()
-        factories.AssignmentGrouping.create(assignment=assignment, grouping=course)
-        db_session.flush()
-
-        assert db_session.scalars(svc.get_assignments(course_id=course.id)).all() == [
-            assignment
-        ]
-
-    def test_get_assignments_with_instructor_h_userid(self, svc, db_session):
-        factories.User()  # User not in assignment
-        assignment = factories.Assignment()
         user = factories.User()
-        lti_role = factories.LTIRole(scope=RoleScope.COURSE)
+        lti_role = factories.LTIRole(scope=RoleScope.COURSE, type=RoleType.INSTRUCTOR)
         factories.AssignmentMembership.create(
             assignment=assignment, user=user, lti_role=lti_role
         )
-        # Other membership record, with a different role
         factories.AssignmentMembership.create(
             assignment=assignment, user=user, lti_role=factories.LTIRole()
         )
-
+        factories.AssignmentGrouping.create(assignment=assignment, grouping=course)
         db_session.flush()
 
-        assert db_session.scalars(svc.get_assignments(user.h_userid)).all() == [
-            assignment
-        ]
+        query_parameters = {}
 
-    def test_get_assignments_with_h_userids(self, svc, db_session):
-        factories.User()  # User not in assignment
-        assignment = factories.Assignment()
-        user = factories.User()
-        lti_role = factories.LTIRole(scope=RoleScope.COURSE)
-        factories.AssignmentMembership.create(
-            assignment=assignment, user=user, lti_role=lti_role
-        )
-        # Other membership record, with a different role
-        factories.AssignmentMembership.create(
-            assignment=assignment, user=user, lti_role=factories.LTIRole()
-        )
+        if instructor_h_userid:
+            query_parameters["instructor_h_userid"] = user.h_userid
 
-        db_session.flush()
+        if course_id:
+            query_parameters["course_id"] = course.id
 
-        assert db_session.scalars(
-            svc.get_assignments(h_userids=[user.h_userid])
-        ).all() == [assignment]
+        if h_userids:
+            query_parameters["h_userids"] = [user.h_userid]
+
+        query = svc.get_assignments(**query_parameters)
+
+        if not query_parameters:
+            assert set(db_session.scalars(query).all()) == set(
+                [assignment] + with_assignment_noise
+            )
+
+        else:
+            assert db_session.scalars(query).all() == [assignment]
 
     def test_get_assignments_by_course_id_with_duplicate(self, db_session, svc):
         course = factories.Course()
@@ -357,14 +354,16 @@ def non_matching_params(self, request, matching_params):
 
     @pytest.fixture(autouse=True)
     def with_assignment_noise(self, assignment):
-        factories.Assignment(
-            tool_consumer_instance_guid=assignment.tool_consumer_instance_guid,
-            resource_link_id="noise_resource_link_id",
-        )
-        factories.Assignment(
-            tool_consumer_instance_guid="noise_tool_consumer_instance_guid",
-            resource_link_id=assignment.resource_link_id,
-        )
+        return [
+            factories.Assignment(
+                tool_consumer_instance_guid=assignment.tool_consumer_instance_guid,
+                resource_link_id="noise_resource_link_id",
+            ),
+            factories.Assignment(
+                tool_consumer_instance_guid="noise_tool_consumer_instance_guid",
+                resource_link_id=assignment.resource_link_id,
+            ),
+        ]
 
     @pytest.fixture
     def create_assignment(self, svc):