Add a get_course_cohorts function and test

common/djangoapps/course_groups/models.py

@@ -40,9 +40,9 @@ def get_cohort(user, course_id):
     Returns:
         A CourseUserGroup object if the User has a cohort, or None.
     """
-    group_type = CourseUserGroup.COHORT
     try:
-        group = CourseUserGroup.objects.get(course_id=course_id, group_type=group_type,
+        group = CourseUserGroup.objects.get(course_id=course_id,
+                                            group_type=CourseUserGroup.COHORT,
                                             users__id=user.id)
     except CourseUserGroup.DoesNotExist:
         group = None
@@ -52,3 +52,16 @@ def get_cohort(user, course_id):
 
     # TODO: add auto-cohorting logic here
     return None
+
+def get_course_cohorts(course_id):
+    """
+    Get a list of all the cohorts in the given course.
+
+    Arguments:
+        course_id: string in the format 'org/course/run'
+
+    Returns:
+        A list of CourseUserGroup objects.  Empty if there are no cohorts.
+    """
+    return list(CourseUserGroup.objects.filter(course_id=course_id,
+                                               group_type=CourseUserGroup.COHORT))

common/djangoapps/course_groups/tests/tests.py

+import django.test
 from django.contrib.auth.models import User
-from nose.tools import assert_equals
 
-from course_groups.models import CourseUserGroup, get_cohort
+from course_groups.models import CourseUserGroup, get_cohort, get_course_cohorts
 
-def test_get_cohort():
+class TestCohorts(django.test.TestCase):
+
+    def test_get_cohort(self):
         course_id = "a/b/c"
         cohort = CourseUserGroup.objects.create(name="TestCohort", course_id=course_id,
                                group_type=CourseUserGroup.COHORT)
@@ -14,8 +16,29 @@ def test_get_cohort():
         cohort.users.add(user)
 
         got = get_cohort(user, course_id)
-    assert_equals(got.id, cohort.id, "Should find the right cohort")
+        self.assertEquals(got.id, cohort.id, "Should find the right cohort")
 
         got = get_cohort(other_user, course_id)
-    assert_equals(got, None, "other_user shouldn't have a cohort")
+        self.assertEquals(got, None, "other_user shouldn't have a cohort")
+
+
+    def test_get_course_cohorts(self):
+        course1_id = "a/b/c"
+        course2_id = "e/f/g"
+
+        # add some cohorts to course 1
+        cohort = CourseUserGroup.objects.create(name="TestCohort",
+                                                course_id=course1_id,
+                                                group_type=CourseUserGroup.COHORT)
+
+        cohort = CourseUserGroup.objects.create(name="TestCohort2",
+                                                course_id=course1_id,
+                                                group_type=CourseUserGroup.COHORT)
+
+
+        # second course should have no cohorts
+        self.assertEqual(get_course_cohorts(course2_id), [])
+
+        cohorts = sorted([c.name for c in get_course_cohorts(course1_id)])
+        self.assertEqual(cohorts, ['TestCohort', 'TestCohort2'])