Add and clean up __repr__ and __str__ for XModule-related things

common/lib/xmodule/xmodule/modulestore/mongo/base.py

@@ -151,12 +151,28 @@ class MongoKeyValueStore(InheritanceKeyValueStore):
         else:
             return False
 
+    def __repr__(self):
+        return "MongoKeyValueStore{!r}<{!r}, {!r}>".format(
+            (self._data, self._parent, self._children, self._metadata),
+            self._fields,
+            self.inherited_settings
+        )
+
 
 class CachingDescriptorSystem(MakoDescriptorSystem, EditInfoRuntimeMixin):
     """
     A system that has a cache of module json that it will use to load modules
     from, with a backup of calling to the underlying modulestore for more data
     """
+    def __repr__(self):
+        return "CachingDescriptorSystem{!r}".format((
+            self.modulestore,
+            unicode(self.course_id),
+            [unicode(key) for key in self.module_data.keys()],
+            self.default_class,
+            [unicode(key) for key in self.cached_metadata.keys()],
+        ))
+
     def __init__(self, modulestore, course_key, module_data, default_class, cached_metadata, **kwargs):
         """
         modulestore: the module store that can be used to retrieve additional modules

common/lib/xmodule/xmodule/x_module.py

@@ -1596,8 +1596,13 @@ class ModuleSystem(MetricsMixin, ConfigurableFragmentWrapper, Runtime):  # pylin
         """provide uniform access to attributes (like etree)"""
         self.__dict__[attr] = val
 
-    def __str__(self):
-        return str(self.__dict__)
+    def __repr__(self):
+        kwargs = self.__dict__.copy()
+
+        # Remove value set transiently by XBlock
+        kwargs.pop('_view_name')
+
+        return "{}{}".format(self.__class__.__name__, kwargs)
 
     @property
     def ajax_url(self):

lms/djangoapps/lms_xblock/field_data.py

@@ -33,3 +33,6 @@ class LmsFieldData(SplitFieldData):
             Scope.user_info: student_data,
             Scope.preferences: student_data,
         })
+
+    def __repr__(self):
+        return "LmsFieldData{!r}".format((self._authored_data, self._student_data))