Add roundtrip test for malformed module

* also fix error message in backcompat_module

common/lib/xmodule/tests/test_import.py

@@ -9,11 +9,9 @@ from xmodule.modulestore import Location
 class ImportTestCase(unittest.TestCase):
     '''Make sure module imports work properly, including for malformed inputs'''
 
-    def test_fallback(self):
-        '''Make sure that malformed xml loads as a MalformedDescriptorb.'''
-
-        bad_xml = '''<sequential display_name="oops"><video url="hi"></sequential>'''
-
+    @staticmethod
+    def get_system():
+        '''Get a dummy system'''
         # Shouldn't need any system params, because the initial parse should fail
         def load_item(loc):
             raise Exception("Shouldn't be called")
@@ -31,8 +29,35 @@ class ImportTestCase(unittest.TestCase):
                                   ignore_errors_handler, process_xml)
         system.render_template = render_template
 
+        return system
+
+    def test_fallback(self):
+        '''Make sure that malformed xml loads as a MalformedDescriptorb.'''
+
+        bad_xml = '''<sequential display_name="oops"><video url="hi"></sequential>'''
+
+        system = self.get_system()
+
         descriptor = XModuleDescriptor.load_from_xml(bad_xml, system, 'org', 'course',
                                                      None)
 
         self.assertEqual(descriptor.__class__.__name__,
                          'MalformedDescriptor')
+
+    def test_reimport(self):
+        '''Make sure an already-exported malformed xml tag loads properly'''
+
+        bad_xml = '''<sequential display_name="oops"><video url="hi"></sequential>'''
+        system = self.get_system()
+        descriptor = XModuleDescriptor.load_from_xml(bad_xml, system, 'org', 'course',
+                                                     None)
+        resource_fs = None
+        tag_xml = descriptor.export_to_xml(resource_fs)
+        re_import_descriptor = XModuleDescriptor.load_from_xml(tag_xml, system,
+                                                               'org', 'course',
+                                                               None)
+        self.assertEqual(re_import_descriptor.__class__.__name__,
+                         'MalformedDescriptor')
+
+        self.assertEqual(descriptor.definition['data'],
+                         re_import_descriptor.definition['data'])

common/lib/xmodule/xmodule/backcompat_module.py

@@ -32,7 +32,7 @@ def process_includes(fn):
                 # read in and convert to XML
                 incxml = etree.XML(ifp.read())
 
-                # insert  new XML into tree in place of inlcude
+                # insert  new XML into tree in place of include
                 parent.insert(parent.index(next_include), incxml)
             except Exception:
                 msg = "Error in problem xml include: %s" % (etree.tostring(next_include, pretty_print=True))