Allow author to cap enrollments in course

add a test case for enrollment caps

pep8 fix

CHANGELOG.rst

@@ -193,6 +193,8 @@ it pauses on the end time.
 
 Blades: Disallow users to enter video url's in http.
 
+Studio/LMS: Ability to cap the max number of active enrollments in a course
+
 LMS: Improve the acessibility of the forum follow post buttons.
 
 Blades: Latex problems are now enabled via use_latex_compiler

common/djangoapps/student/models.py

@@ -424,6 +424,28 @@ class CourseEnrollment(models.Model):
 
         return enrollment
 
+    @classmethod
+    def num_enrolled_in(cls, course_id):
+        """
+        Returns the count of active enrollments in a course.
+
+        'course_id' is the course_id to return enrollments
+        """
+        enrollment_number = CourseEnrollment.objects.filter(course_id=course_id, is_active=1).count()
+
+        return enrollment_number
+
+    @classmethod
+    def is_course_full(cls, course):
+        """
+        Returns a boolean value regarding whether a course has already reached it's max enrollment
+        capacity
+        """
+        is_course_full = False
+        if course.max_student_enrollments_allowed is not None:
+            is_course_full = cls.num_enrolled_in(course.location.course_id) >= course.max_student_enrollments_allowed
+        return is_course_full
+
     def update_enrollment(self, mode=None, is_active=None):
         """
         Updates an enrollment for a user in a class.  This includes options

common/djangoapps/student/views.py

@@ -561,6 +561,12 @@ def change_enrollment(request):
         if not has_access(user, course, 'enroll'):
             return HttpResponseBadRequest(_("Enrollment is closed"))
 
+        # see if we have already filled up all allowed enrollments
+        is_course_full = CourseEnrollment.is_course_full(course)
+
+        if is_course_full:
+            return HttpResponseBadRequest(_("Course is full"))
+
         # If this course is available in multiple modes, redirect them to a page
         # where they can choose which mode they want.
         available_modes = CourseMode.modes_for_course(course_id)

common/lib/xmodule/xmodule/course_module.py

@@ -13,7 +13,7 @@ from xmodule.seq_module import SequenceDescriptor, SequenceModule
 from xmodule.graders import grader_from_conf
 import json
 
-from xblock.fields import Scope, List, String, Dict, Boolean
+from xblock.fields import Scope, List, String, Dict, Boolean, Integer
 from .fields import Date
 from xmodule.modulestore.locator import CourseLocator
 from django.utils.timezone import UTC
@@ -384,6 +384,9 @@ class CourseFields(object):
     display_coursenumber = String(help="An optional display string for the course number that will get rendered in the LMS",
                                   scope=Scope.settings)
 
+    max_student_enrollments_allowed = Integer(help="Limit the number of students allowed to enroll in this course.",
+                                              scope=Scope.settings)
+
 class CourseDescriptor(CourseFields, SequenceDescriptor):
     module_class = SequenceModule
 

lms/djangoapps/courseware/tests/test_about.py

@@ -51,3 +51,54 @@ class AboutTestCase(LoginEnrollmentTestCase, ModuleStoreTestCase):
         resp = self.client.get(url)
         self.assertEqual(resp.status_code, 200)
         self.assertIn(self.xml_data, resp.content)
+
+
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
+class AboutWithCappedEnrollmentsTestCase(LoginEnrollmentTestCase, ModuleStoreTestCase):
+    """
+    This test case will check the About page when a course has a capped enrollment
+    """
+    def setUp(self):
+        """
+        Set up the tests
+        """
+        self.course = CourseFactory.create(metadata={"max_student_enrollments_allowed": 1})
+
+        self.about = ItemFactory.create(
+            category="about", parent_location=self.course.location,
+            data="OOGIE BLOOGIE", display_name="overview"
+        )
+        # The following XML course is closed; we're testing that
+        # an about page still appears when the course is already closed
+        self.xml_course_id = 'edX/detached_pages/2014'
+        self.xml_data = "about page 463139"
+
+    def test_enrollment_cap(self):
+        """
+        This test will make sure that enrollment caps are enforced
+        """
+        self.setup_user()
+        url = reverse('about_course', args=[self.course.id])
+        resp = self.client.get(url)
+        self.assertEqual(resp.status_code, 200)
+        self.assertIn('<a href="#" class="register">', resp.content)
+
+        self.enroll(self.course, verify=True)
+
+        # create a new account since the first account is already registered for the course
+        self.email = 'foo_second@test.com'
+        self.password = 'bar'
+        self.username = 'test_second'
+        self.create_account(self.username,
+                            self.email, self.password)
+        self.activate_user(self.email)
+        self.login(self.email, self.password)
+
+        # Get the about page again and make sure that the page says that the course is full
+        resp = self.client.get(url)
+        self.assertEqual(resp.status_code, 200)
+        self.assertIn("Course is full", resp.content)
+
+        # Try to enroll as well
+        result = self.enroll(self.course)
+        self.assertFalse(result)

lms/djangoapps/courseware/views.py

@@ -562,6 +562,9 @@ def course_about(request, course_id):
         reg_then_add_to_cart_link = "{reg_url}?course_id={course_id}&enrollment_action=add_to_cart".format(
             reg_url=reverse('register_user'), course_id=course.id)
 
+    # see if we have already filled up all allowed enrollments
+    is_course_full = CourseEnrollment.is_course_full(course)
+
     return render_to_response('courseware/course_about.html',
                               {'course': course,
                                'registered': registered,
@@ -569,7 +572,8 @@ def course_about(request, course_id):
                                'registration_price': registration_price,
                                'in_cart': in_cart,
                                'reg_then_add_to_cart_link': reg_then_add_to_cart_link,
-                               'show_courseware_link': show_courseware_link})
+                               'show_courseware_link': show_courseware_link,
+                               'is_course_full': is_course_full})
 
 
 @ensure_csrf_cookie

lms/djangoapps/instructor/views/instructor_dashboard.py

@@ -115,7 +115,7 @@ def _section_course_info(course_id, access):
         'course_num': course_num,
         'course_name': course_name,
         'course_display_name': course.display_name,
-        'enrollment_count': CourseEnrollment.objects.filter(course_id=course_id, is_active=1).count(),
+        'enrollment_count': CourseEnrollment.num_enrolled_in(course_id),
         'has_started': course.has_started(),
         'has_ended': course.has_ended(),
         'list_instructor_tasks_url': reverse('list_instructor_tasks', kwargs={'course_id': course_id}),

lms/djangoapps/instructor/views/legacy.py

@@ -110,7 +110,7 @@ def instructor_dashboard(request, course_id):
     else:
         idash_mode = request.session.get('idash_mode', 'Grades')
 
-    enrollment_number = CourseEnrollment.objects.filter(course_id=course_id, is_active=1).count()
+    enrollment_number = CourseEnrollment.num_enrolled_in(course_id)
 
     # assemble some course statistics for output to instructor
     def get_course_stats_table():

lms/templates/courseware/course_about.html

@@ -166,6 +166,10 @@
                       cost=registration_price)}
           </a>
           <div id="register_error"></div>
+        % elif is_course_full:
+          <span class="register disabled">
+            ${_("Course is full")}
+          </span>          
         %else:
           <a href="#" class="register">
             ${_("Register for {course.display_number_with_default}").format(course=course) | h}