refactor: deprecates ModuleSystem.render_template

in favor of the added MakoSystem render_template method.

Related changes:
* Adds the MakoService to the StudioEditModuleRuntime,
  PreviewModuleSystem, LmsModuleSystem, and XBlockRuntime
* MakoService constructor takes a `namespace_prefix` string, so that the
  CMS PreviewModuleSystem can render to LMS templates, without needing
  the special render_from_lms helper method.
* ModuleSystem.render_template becomes a read-only property, so the
  constructor calls and test module systems are updated accordingly.
* Adds tests for the MakoService and module system shims.

lms/djangoapps/courseware/module_render.py

@@ -52,7 +52,6 @@ from lms.djangoapps.courseware.masquerade import (
     setup_masquerade
 )
 from lms.djangoapps.courseware.model_data import DjangoKeyValueStore, FieldDataCache
-from common.djangoapps.edxmako.shortcuts import render_to_string
 from lms.djangoapps.courseware.field_overrides import OverrideFieldData
 from lms.djangoapps.courseware.services import UserStateService
 from lms.djangoapps.grades.api import GradesUtilService
@@ -90,6 +89,7 @@ from common.djangoapps.student.roles import CourseBetaTesterRole
 from common.djangoapps.track import contexts
 from common.djangoapps.util import milestones_helpers
 from common.djangoapps.util.json_request import JsonResponse
+from common.djangoapps.edxmako.services import MakoService
 from common.djangoapps.xblock_django.user_service import DjangoXBlockUserService
 from xmodule.contentstore.django import contentstore
 from xmodule.error_module import ErrorBlock, NonStaffErrorBlock
@@ -703,6 +703,7 @@ def get_module_system_for_user(
     if is_masquerading_as_specific_student(user, course_id):
         block_wrappers.append(filter_displayed_blocks)
 
+    mako_service = MakoService()
     if settings.FEATURES.get("LICENSING", False):
         block_wrappers.append(wrap_with_license)
 
@@ -770,7 +771,6 @@ def get_module_system_for_user(
 
     system = LmsModuleSystem(
         track_function=track_function,
-        render_template=render_to_string,
         static_url=settings.STATIC_URL,
         xqueue=xqueue,
         # TODO (cpennington): Figure out how to share info between systems
@@ -810,6 +810,7 @@ def get_module_system_for_user(
         services={
             'fs': FSService(),
             'field-data': field_data,
+            'mako': mako_service,
             'user': user_service,
             'verification': XBlockVerificationService(),
             'proctoring': ProctoringService(),

lms/djangoapps/courseware/tests/helpers.py

@@ -7,6 +7,7 @@ import ast
 import json
 from collections import OrderedDict
 from datetime import timedelta
+from unittest.mock import Mock
 
 from django.contrib import messages
 from django.contrib.auth.models import User  # lint-amnesty, pylint: disable=imported-auth-user
@@ -63,11 +64,11 @@ class BaseTestXmodule(ModuleStoreTestCase):
     METADATA = {}
     MODEL_DATA = {'data': '<some_module></some_module>'}
 
-    def new_module_runtime(self):
+    def new_module_runtime(self, render_template=None):
         """
         Generate a new ModuleSystem that is minimally set up for testing
         """
-        return get_test_system(course_id=self.course.id)
+        return get_test_system(course_id=self.course.id, render_template=render_template)
 
     def new_descriptor_runtime(self):
         runtime = get_test_descriptor_system()
@@ -143,12 +144,14 @@ class BaseTestXmodule(ModuleStoreTestCase):
 
 class XModuleRenderingTestBase(BaseTestXmodule):  # lint-amnesty, pylint: disable=missing-class-docstring
 
-    def new_module_runtime(self):
+    def new_module_runtime(self, render_template=None):
         """
         Create a runtime that actually does html rendering
         """
-        runtime = super().new_module_runtime()
-        runtime.render_template = render_to_string
+        if not render_template:
+            render_template = render_to_string
+        runtime = super().new_module_runtime(render_template=render_template)
+        runtime.modulestore = Mock()
         return runtime
 
 

lms/djangoapps/courseware/tests/test_discussion_xblock.py

@@ -42,7 +42,6 @@ class TestDiscussionXBlock(XModuleRenderingTestBase):
         self.patchers = []
         self.course_id = "test_course"
         self.runtime = self.new_module_runtime()
-        self.runtime.modulestore = mock.Mock()
 
         self.discussion_id = str(uuid.uuid4())
         self.data = DictFieldData({
@@ -131,7 +130,8 @@ class TestViews(TestDiscussionXBlock):
         self.template_canary = 'canary'
         self.render_template = mock.Mock()
         self.render_template.return_value = self.template_canary
-        self.block.runtime.render_template = self.render_template
+        self.runtime = self.new_module_runtime(render_template=self.render_template)
+        self.block.runtime = self.runtime
         self.has_permission_mock = mock.Mock()
         self.has_permission_mock.return_value = False
         self.block.has_permission = self.has_permission_mock

lms/djangoapps/courseware/tests/test_module_render.py

@@ -2687,3 +2687,17 @@ class LmsModuleSystemShimTest(SharedModuleStoreTestCase):
         assert runtime.seed == 0
         assert runtime.user_id is None
         assert not runtime.user_is_staff
+
+    def test_render_template(self):
+        runtime, _ = render.get_module_system_for_user(
+            self.user,
+            self.student_data,
+            self.descriptor,
+            self.course.id,
+            self.track_function,
+            self.xqueue_callback_url_prefix,
+            self.request_token,
+            course=self.course,
+        )
+        rendered = runtime.render_template('templates/edxmako.html', {'element_id': 'hi'})  # pylint: disable=not-callable
+        assert rendered == '<div id="hi" ns="main">Testing the MakoService</div>\n'

lms/djangoapps/lms_xblock/test/test_runtime.py

@@ -63,7 +63,6 @@ class TestHandlerUrl(TestCase):
             static_url='/static',
             track_function=Mock(),
             get_module=Mock(),
-            render_template=Mock(),
             replace_urls=str,
             course_id=self.course_key,
             user=Mock(),
@@ -130,7 +129,6 @@ class TestUserServiceAPI(TestCase):
             static_url='/static',
             track_function=Mock(),
             get_module=Mock(),
-            render_template=Mock(),
             replace_urls=str,
             user=self.user,
             course_id=self.course_id,
@@ -186,7 +184,6 @@ class TestBadgingService(ModuleStoreTestCase):
             static_url='/static',
             track_function=Mock(),
             get_module=Mock(),
-            render_template=Mock(),
             replace_urls=str,
             course_id=self.course_id,
             user=self.user,
@@ -242,7 +239,6 @@ class TestI18nService(ModuleStoreTestCase):
             static_url='/static',
             track_function=Mock(),
             get_module=Mock(),
-            render_template=Mock(),
             replace_urls=str,
             course_id=self.course.id,
             user=Mock(),

lms/envs/test.py

@@ -495,6 +495,20 @@ ENTERPRISE_CONSENT_API_URL = 'http://enterprise.example.com/consent/api/v1/'
 ACTIVATION_EMAIL_FROM_ADDRESS = 'test_activate@edx.org'
 
 TEMPLATES[0]['OPTIONS']['debug'] = True
+TEMPLATES.append(
+    {
+        # This separate copy of the Mako backend is used to test rendering previews in the 'lms.main' namespace
+        'NAME': 'preview',
+        'BACKEND': 'common.djangoapps.edxmako.backend.Mako',
+        'APP_DIRS': False,
+        'DIRS': MAKO_TEMPLATE_DIRS_BASE,
+        'OPTIONS': {
+            'context_processors': CONTEXT_PROCESSORS,
+            'debug': False,
+            'namespace': 'lms.main',
+        }
+    }
+)
 
 ########################## VIDEO TRANSCRIPTS STORAGE ############################
 VIDEO_TRANSCRIPTS_SETTINGS = dict(