Remove unused imports. Push model imports down into relevant methods.

Mock out the static_replace modules in the proper location.

common/djangoapps/static_replace/__init__.py

@@ -5,9 +5,6 @@ from django.contrib.staticfiles.storage import staticfiles_storage
 from django.contrib.staticfiles import finders
 from django.conf import settings
 
-from static_replace.models import AssetBaseUrlConfig, AssetExcludedExtensionsConfig
-from xmodule.modulestore.django import modulestore
-from xmodule.modulestore import ModuleStoreEnum
 from xmodule.contentstore.content import StaticContent
 
 from opaque_keys.edx.locator import AssetLocator
@@ -191,6 +188,8 @@ def replace_static_urls(text, data_directory=None, course_id=None, static_asset_
             else:
                 # if not, then assume it's courseware specific content and then look in the
                 # Mongo-backed database
+                # Import is placed here to avoid model import at project startup.
+                from static_replace.models import AssetBaseUrlConfig, AssetExcludedExtensionsConfig
                 base_url = AssetBaseUrlConfig.get_base_url()
                 excluded_exts = AssetExcludedExtensionsConfig.get_excluded_extensions()
                 url = StaticContent.get_canonicalized_asset_path(course_id, rest, base_url, excluded_exts)

common/djangoapps/static_replace/test/test_static_replace.py

@@ -116,9 +116,9 @@ def test_storage_url_not_exists(mock_storage):
 
 
 @patch('static_replace.StaticContent', autospec=True)
-@patch('static_replace.modulestore', autospec=True)
-@patch('static_replace.AssetBaseUrlConfig.get_base_url')
-@patch('static_replace.AssetExcludedExtensionsConfig.get_excluded_extensions')
+@patch('xmodule.modulestore.django.modulestore', autospec=True)
+@patch('static_replace.models.AssetBaseUrlConfig.get_base_url')
+@patch('static_replace.models.AssetExcludedExtensionsConfig.get_excluded_extensions')
 def test_mongo_filestore(mock_get_excluded_extensions, mock_get_base_url, mock_modulestore, mock_static_content):
 
     mock_modulestore.return_value = Mock(MongoModuleStore)
@@ -139,7 +139,7 @@ def test_mongo_filestore(mock_get_excluded_extensions, mock_get_base_url, mock_m
 
 
 @patch('static_replace.settings', autospec=True)
-@patch('static_replace.modulestore', autospec=True)
+@patch('xmodule.modulestore.django.modulestore', autospec=True)
 @patch('static_replace.staticfiles_storage', autospec=True)
 def test_data_dir_fallback(mock_storage, mock_modulestore, mock_settings):
     mock_modulestore.return_value = Mock(XMLModuleStore)
@@ -165,7 +165,7 @@ def test_raw_static_check():
 
 @pytest.mark.django_db
 @patch('static_replace.staticfiles_storage', autospec=True)
-@patch('static_replace.modulestore', autospec=True)
+@patch('xmodule.modulestore.django.modulestore', autospec=True)
 def test_static_url_with_query(mock_modulestore, mock_storage):
     """
     Make sure that for urls with query params:
@@ -201,7 +201,7 @@ def test_regex():
 
 
 @patch('static_replace.staticfiles_storage', autospec=True)
-@patch('static_replace.modulestore', autospec=True)
+@patch('xmodule.modulestore.django.modulestore', autospec=True)
 def test_static_url_with_xblock_resource(mock_modulestore, mock_storage):
     """
     Make sure that for URLs with XBlock resource URL, which start with /static/,
@@ -216,7 +216,7 @@ def test_static_url_with_xblock_resource(mock_modulestore, mock_storage):
 
 
 @patch('static_replace.staticfiles_storage', autospec=True)
-@patch('static_replace.modulestore', autospec=True)
+@patch('xmodule.modulestore.django.modulestore', autospec=True)
 @override_settings(STATIC_URL='https://example.com/static/')
 def test_static_url_with_xblock_resource_on_cdn(mock_modulestore, mock_storage):
     """

common/lib/xmodule/xmodule/modulestore/django.py

@@ -29,7 +29,6 @@ from xmodule.contentstore.django import contentstore
 from xmodule.modulestore.draft_and_published import BranchSettingMixin
 from xmodule.modulestore.mixed import MixedModuleStore
 from xmodule.util.django import get_current_request_hostname
-import xblock.reference.plugins
 
 try:
     # We may not always have the request_cache module available
@@ -245,6 +244,9 @@ def create_modulestore_instance(
     """
     This will return a new instance of a modulestore given an engine and options
     """
+    # Import is placed here to avoid model import at project startup.
+    import xblock.reference.plugins
+
     class_ = load_function(engine)
 
     _options = {}

lms/djangoapps/branding/__init__.py

@@ -10,7 +10,6 @@ such as the site visible courses, university name and logo.
 from django.conf import settings
 
 from opaque_keys.edx.keys import CourseKey
-from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
 from openedx.core.djangoapps.site_configuration import helpers as configuration_helpers
 
 
@@ -25,6 +24,9 @@ def get_visible_courses(org=None, filter_=None):
         filter_ (dict): Optional parameter that allows custom filtering by
             fields on the course.
     """
+    # Import is placed here to avoid model import at project startup.
+    from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
+
     courses = []
     current_site_orgs = configuration_helpers.get_current_site_orgs()
 

lms/djangoapps/commerce/signals.py

@@ -10,12 +10,9 @@ from urlparse import urljoin
 import requests
 from django.conf import settings
 from django.contrib.auth import get_user_model
-from django.contrib.auth.models import AnonymousUser
 from django.dispatch import receiver
 from django.utils.translation import ugettext as _
 
-from commerce.models import CommerceConfiguration
-from openedx.core.djangoapps.commerce.utils import ecommerce_api_client, is_commerce_service_configured
 from openedx.core.djangoapps.site_configuration import helpers as configuration_helpers
 from openedx.core.djangoapps.theming import helpers as theming_helpers
 from request_cache.middleware import RequestCache
@@ -31,6 +28,10 @@ def handle_refund_order(sender, course_enrollment=None, **kwargs):
     Signal receiver for unenrollments, used to automatically initiate refunds
     when applicable.
     """
+    # Import is placed here to avoid model import at project startup.
+    from django.contrib.auth.models import AnonymousUser
+    from openedx.core.djangoapps.commerce.utils import is_commerce_service_configured
+
     if not is_commerce_service_configured():
         return
 
@@ -83,6 +84,10 @@ def refund_seat(course_enrollment):
         exceptions.SlumberBaseException: for any unhandled HTTP error during communication with the E-Commerce Service.
         exceptions.Timeout: if the attempt to reach the commerce service timed out.
     """
+    # Import is placed here to avoid model import at project startup.
+    from commerce.models import CommerceConfiguration
+    from openedx.core.djangoapps.commerce.utils import ecommerce_api_client
+
     User = get_user_model()  # pylint:disable=invalid-name
     course_key_str = unicode(course_enrollment.course_id)
     enrollee = course_enrollment.user

openedx/core/djangoapps/coursegraph/tasks.py

@@ -13,10 +13,8 @@ from opaque_keys.edx.keys import CourseKey
 from py2neo import Graph, Node, Relationship, authenticate, NodeSelector
 from py2neo.compat import integer, string, unicode as neo4j_unicode
 from request_cache.middleware import RequestCache
-from xmodule.modulestore.django import modulestore
 from xmodule.modulestore.store_utilities import DETACHED_XBLOCK_TYPES
 
-from openedx.core.djangoapps.content.course_structures.models import CourseStructure
 
 log = logging.getLogger(__name__)
 celery_log = logging.getLogger('edx.celery.task')
@@ -135,6 +133,8 @@ def get_course_last_published(course_key):
         text, or None, if there's no record of the last time this course
         was published.
     """
+    # Import is placed here to avoid model import at project startup.
+    from openedx.core.djangoapps.content.course_structures.models import CourseStructure
     try:
         structure = CourseStructure.objects.get(course_id=course_key)
         course_last_published_date = six.text_type(structure.modified)
@@ -154,6 +154,9 @@ def serialize_course(course_id):
         nodes: a list of py2neo Node objects
         relationships: a list of py2neo Relationships objects
     """
+    # Import is placed here to avoid model import at project startup.
+    from xmodule.modulestore.django import modulestore
+
     # create a location to node mapping we'll need later for
     # writing relationships
     location_to_node = {}
@@ -292,6 +295,8 @@ class ModuleStoreSerializer(object):
                 For example, ["course-v1:org+course+run"].
             skip: Also a list of string serializations of course keys.
         """
+        # Import is placed here to avoid model import at project startup.
+        from xmodule.modulestore.django import modulestore
         if courses:
             course_keys = [CourseKey.from_string(course.strip()) for course in courses]
         else:

openedx/core/djangoapps/credit/signals.py

@@ -9,7 +9,6 @@ from django.utils import timezone
 from opaque_keys.edx.keys import CourseKey
 
 from openedx.core.djangoapps.signals.signals import COURSE_GRADE_CHANGED
-from xmodule.modulestore.django import SignalHandler
 
 log = logging.getLogger(__name__)
 

openedx/core/djangoapps/site_configuration/helpers.py

@@ -4,7 +4,6 @@ Helpers methods for site configuration.
 from django.conf import settings
 
 from microsite_configuration import microsite
-from openedx.core.djangoapps.site_configuration.models import SiteConfiguration
 
 
 def get_current_site_configuration():
@@ -20,6 +19,8 @@ def get_current_site_configuration():
     from openedx.core.djangoapps.theming.helpers import get_current_site
     site = get_current_site()
 
+    # Import is placed here to avoid model import at project startup.
+    from openedx.core.djangoapps.site_configuration.models import SiteConfiguration
     try:
         return getattr(site, "configuration", None)
     except SiteConfiguration.DoesNotExist:
@@ -183,6 +184,8 @@ def get_value_for_org(org, val_name, default=None):
     """
     # Here we first look for the asked org inside site configuration, and if org is not present in site configuration
     # then we go ahead and look it inside microsite configuration.
+    # Import is placed here to avoid model import at project startup.
+    from openedx.core.djangoapps.site_configuration.models import SiteConfiguration
     if SiteConfiguration.has_org(org):
         return SiteConfiguration.get_value_for_org(org, val_name, default)
     else:
@@ -212,6 +215,8 @@ def get_all_orgs():
     Returns:
         A list of all organizations present in either microsite configuration or site configuration.
     """
+    # Import is placed here to avoid model import at project startup.
+    from openedx.core.djangoapps.site_configuration.models import SiteConfiguration
     site_configuration_orgs = SiteConfiguration.get_all_orgs()
     microsite_orgs = microsite.get_all_orgs()
 

openedx/core/djangoapps/waffle_utils/__init__.py

@@ -51,10 +51,6 @@ from contextlib import contextmanager
 from opaque_keys.edx.keys import CourseKey
 from request_cache import get_cache as get_request_cache, get_request
 from waffle import flag_is_active, switch_is_active
-from waffle.models import Flag
-from waffle.testutils import override_switch as waffle_override_switch
-
-from .models import WaffleFlagCourseOverrideModel
 
 log = logging.getLogger(__name__)
 
@@ -154,6 +150,8 @@ class WaffleSwitchNamespace(WaffleNamespace):
         contextmanager.
         Note: The value is overridden in the model, not the request cache.
         """
+        # Import is placed here to avoid model import at project startup.
+        from waffle.testutils import override_switch as waffle_override_switch
         namespaced_switch_name = self._namespaced_name(switch_name)
         with waffle_override_switch(namespaced_switch_name, active):
             log.info(u"%sSwitch '%s' set to %s in model.", self.log_prefix, namespaced_switch_name, active)
@@ -206,6 +204,9 @@ class WaffleFlagNamespace(WaffleNamespace):
             flag_undefined_default (Boolean): A default value to be returned if
                 the waffle flag is to be checked, but doesn't exist.
         """
+        # Import is placed here to avoid model import at project startup.
+        from waffle.models import Flag
+
         # validate arguments
         namespaced_flag_name = self._namespaced_name(flag_name)
         value = None
@@ -295,6 +296,8 @@ class CourseWaffleFlag(WaffleFlag):
                 namespaced_flag_name (String): A namespaced version of the flag
                     to check.
             """
+            # Import is placed here to avoid model import at project startup.
+            from .models import WaffleFlagCourseOverrideModel
             cache_key = u'{}.{}'.format(namespaced_flag_name, unicode(course_key))
             force_override = self.waffle_namespace._cached_flags.get(cache_key)
 

openedx/core/djangolib/testing/utils.py

@@ -16,7 +16,6 @@ import crum
 from django import db
 from django.conf import settings
 from django.contrib import sites
-from django.contrib.auth.models import AnonymousUser
 from django.core.cache import caches
 from django.db import DEFAULT_DB_ALIAS, connections
 from django.test import RequestFactory, TestCase, override_settings
@@ -244,6 +243,8 @@ def get_mock_request(user=None):
     """
     Create a request object for the user, if specified.
     """
+    # Import is placed here to avoid model import at project startup.
+    from django.contrib.auth.models import AnonymousUser
     request = RequestFactory().get('/')
     if user is not None:
         request.user = user