diff --git a/cms/djangoapps/contentstore/views/preview.py b/cms/djangoapps/contentstore/views/preview.py
index 8401935c3d..b604fc9555 100644
--- a/cms/djangoapps/contentstore/views/preview.py
+++ b/cms/djangoapps/contentstore/views/preview.py
@@ -95,6 +95,20 @@ class PreviewModuleSystem(ModuleSystem):  # pylint: disable=abstract-method
         return local_resource_url(block, uri)
 
 
+class StudioUserService(object):
+    """
+    Provides a Studio implementation of the XBlock user service.
+    """
+
+    def __init__(self, request):
+        super(StudioUserService, self).__init__()
+        self._request = request
+
+    @property
+    def user_id(self):
+        return self._request.user.id
+
+
 def _preview_module_system(request, descriptor):
     """
     Returns a ModuleSystem for the specified descriptor that is specialized for
@@ -139,6 +153,7 @@ def _preview_module_system(request, descriptor):
         descriptor_runtime=descriptor.runtime,
         services={
             "i18n": ModuleI18nService(),
+            "user": StudioUserService(request),
         },
     )
 
diff --git a/common/lib/xmodule/xmodule/split_test_module.py b/common/lib/xmodule/xmodule/split_test_module.py
index 35154f7466..6d16adedc5 100644
--- a/common/lib/xmodule/xmodule/split_test_module.py
+++ b/common/lib/xmodule/xmodule/split_test_module.py
@@ -343,6 +343,7 @@ class SplitTestModule(SplitTestFields, XModule, StudioEditableModule):
 
 @XBlock.needs('user_tags')  # pylint: disable=abstract-method
 @XBlock.wants('partitions')
+@XBlock.needs('user')
 class SplitTestDescriptor(SplitTestFields, SequenceDescriptor, StudioEditableDescriptor):
     # the editing interface can be the same as for sequences -- just a container
     module_class = SplitTestModule
@@ -553,7 +554,8 @@ class SplitTestDescriptor(SplitTestFields, SequenceDescriptor, StudioEditableDes
         for group in user_partition.groups:
             str_group_id = unicode(group.id)
             if str_group_id not in self.group_id_to_child:
-                self._create_vertical_for_group(group, request.user.id)
+                user_id = self.runtime.service(self, 'user').user_id
+                self._create_vertical_for_group(group, user_id)
                 changed = True
 
         if changed: