Merge pull request #636 from MITx/feature/cale/progress-handle-extra-credit

Feature/cale/progress handle extra credit

common/lib/xmodule/xmodule/capa_module.py

@@ -202,10 +202,8 @@ class CapaModule(XModule):
             try:
                 return Progress(score, total)
             except Exception as err:
-                # TODO (vshnayder): why is this still here? still needed?
-                if self.system.DEBUG:
-                    return None
-                raise
+                log.exception("Got bad progress")
+                return None
         return None
 
     def get_html(self):

common/lib/xmodule/xmodule/progress.py

@@ -39,9 +39,14 @@ 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 a < 0:
+            a = 0
+
+        if b <= 0:
+            raise ValueError('fraction a/b = {0}/{1} must have b > 0'.format(a, b))
 
         self._a = a
         self._b = b