Update the API and Data Layer to get the student from the models.

common/djangoapps/enrollment/api.py

@@ -103,10 +103,7 @@ def get_enrollments(student_id):
         ]
 
     """
-    enrollments = _data_api().get_course_enrollments(student_id)
-    for enrollment in enrollments:
-        enrollment['student'] = student_id
-    return enrollments
+    return _data_api().get_course_enrollments(student_id)
 
 
 def get_enrollment(student_id, course_id):
@@ -148,9 +145,7 @@ def get_enrollment(student_id, course_id):
         }
 
     """
-    enrollment = _data_api().get_course_enrollment(student_id, course_id)
-    enrollment['student'] = student_id
-    return enrollment
+    return _data_api().get_course_enrollment(student_id, course_id)
 
 
 def add_enrollment(student_id, course_id, mode='honor', is_active=True):
@@ -196,9 +191,7 @@ def add_enrollment(student_id, course_id, mode='honor', is_active=True):
         }
     """
     _validate_course_mode(course_id, mode)
-    enrollment = _data_api().update_course_enrollment(student_id, course_id, mode=mode, is_active=is_active)
-    enrollment['student'] = student_id
-    return enrollment
+    return _data_api().update_course_enrollment(student_id, course_id, mode=mode, is_active=is_active)
 
 
 def deactivate_enrollment(student_id, course_id):
@@ -246,9 +239,7 @@ def deactivate_enrollment(student_id, course_id):
             u"No enrollment was found for student {student} in course {course}"
             .format(student=student_id, course=course_id)
         )
-    enrollment = _data_api().update_course_enrollment(student_id, course_id, is_active=False)
-    enrollment['student'] = student_id
-    return enrollment
+    return _data_api().update_course_enrollment(student_id, course_id, is_active=False)
 
 
 def update_enrollment(student_id, course_id, mode):
@@ -292,9 +283,7 @@ def update_enrollment(student_id, course_id, mode):
 
     """
     _validate_course_mode(course_id, mode)
-    enrollment = _data_api().update_course_enrollment(student_id, course_id, mode)
-    enrollment['student'] = student_id
-    return enrollment
+    return _data_api().update_course_enrollment(student_id, course_id, mode)
 
 
 def get_course_enrollment_details(course_id):

common/djangoapps/enrollment/serializers.py

@@ -54,10 +54,15 @@ class CourseEnrollmentSerializer(serializers.ModelSerializer):
 
     """
     course = CourseField()
+    student = serializers.SerializerMethodField('get_username')
+
+    def get_username(self, model):
+        """Retrieves the username from the associated model."""
+        return model.username
 
     class Meta:  # pylint: disable=C0111
         model = CourseEnrollment
-        fields = ('created', 'mode', 'is_active', 'course')
+        fields = ('created', 'mode', 'is_active', 'course', 'student')
         lookup_field = 'username'
 
 

common/djangoapps/enrollment/tests/test_data.py

@@ -156,6 +156,7 @@ class EnrollmentDataTest(ModuleStoreTestCase):
         )
         # Get the enrollment and compare it to the original.
         result = data.get_course_enrollment(self.user.username, unicode(self.course.id))
+        self.assertEqual(self.user.username, result['student'])
         self.assertEqual(enrollment, result)
 
     @raises(NonExistentCourseError)