Make progress handle extra credit by capping at 100%, and handle malformed…

Make progress handle extra credit by capping at 100%, and handle malformed progress stuff by ignoring any changes

common/lib/xmodule/xmodule/capa_module.py

@@ -322,10 +322,16 @@ class CapaModule(XModule):
 
         before = self.get_progress()
         d = handlers[dispatch](get)
-        after = self.get_progress()
-        d.update({
-            'progress_changed': after != before,
-            'progress_status': Progress.to_js_status_str(after),
+        try:
+            after = self.get_progress()
+            d.update({
+                'progress_changed': after != before,
+                'progress_status': Progress.to_js_status_str(after),
+                })
+        except ValueError:
+            d.update({
+                'progress_changed': False,
+                'progress_status': Progress.to_js_status(before),
             })
         return json.dumps(d, cls=ComplexEncoder)
 

common/lib/xmodule/xmodule/progress.py

@@ -39,9 +39,11 @@ class Progress(object):
                 isinstance(b, numbers.Number)):
             raise TypeError('a and b must be numbers.  Passed {0}/{1}'.format(a, b))
 
-        if not (0 <= a <= b and b > 0):
-            raise ValueError(
-                'fraction a/b = {0}/{1} must have 0 <= a <= b and b > 0'.format(a, b))
+        if a > b:
+            a = b
+
+        if b <= 0:
+            raise ValueError('fraction a/b = {0}/{1} must have b > 0'.format(a, b))
 
         self._a = a
         self._b = b