feat: cache circles and learning units

server/vbv_lernwelt/dashboard/graphql/types/competence.py

@@ -1,6 +1,7 @@
 from typing import List, Tuple
 
 import graphene
+from wagtail.models import Page
 
 from vbv_lernwelt.course.models import CourseCompletion, CourseCompletionStatus
 
@@ -38,25 +39,23 @@ def competences(
     completions = CourseCompletion.objects.filter(
         course_session_id__in=course_session_selection_ids,
         page_type="competence.PerformanceCriteria",
-    )
+    ).prefetch_related("course_session", "page")
 
     if user_selection_ids is not None:
         completions = completions.filter(user_id__in=user_selection_ids)
 
     competence_records = {}
 
-    # purely for performance reasons, since looking up
-    # the circle for each completion is expensive :-/
-    circle_cache = {}
+    unique_page_ids = {completion.page.id for completion in completions}
+    learning_units = {
+        page_id: Page.objects.get(id=page_id).specific.learning_unit
+        for page_id in unique_page_ids
+    }
+    circles = {lu.id: lu.get_circle() for lu in learning_units.values()}
 
     for completion in completions:
-        if completion.page.id not in circle_cache:
-            circle_cache[
-                completion.page.id
-            ] = completion.page.specific.learning_unit.get_circle()
-
-        circle = circle_cache[completion.page.id]
-        learning_unit = completion.page.specific.learning_unit
+        learning_unit = learning_units.get(completion.page.id)
+        circle = circles.get(learning_unit.id)
 
         competence_records.setdefault(circle.id, {}).setdefault(
             learning_unit,

server/vbv_lernwelt/dashboard/tests/graphql/test_competence.py

@@ -18,10 +18,6 @@ class DashboardCompetenceTestCase(GraphQLTestCase):
     GRAPHQL_URL = "/server/graphql/"
 
     def test_competence(self):
-        # TODO: Livioso 30.10.2023
-        #  A test that checks the competence records
-        #  would make sense -> missing (circle, learning unit) nesting!
-
         # GIVEN
         course, course_page = create_course("Test Course")
         course_session = create_course_session(course=course, title="Test Bern 2022 a")