Fix LTI max_score method.

common/lib/xmodule/xmodule/lti_module.py

@@ -375,7 +375,7 @@ oauth_consumer_key="", oauth_signature="frVp4JuvT1mVXlxktiAUjQ7%2F1cw%3D"'}
         return params
 
     def max_score(self):
-        return self.weight
+        return self.weight if self.graded else 0
 
 
     @XBlock.handler

common/lib/xmodule/xmodule/tests/test_lti_unit.py

@@ -249,3 +249,13 @@ class LTIModuleTest(LogicTest):
     def test_client_key_secret(self):
         pass
 
+    def test_max_score(self):
+        self.xmodule.weight = 100.0
+
+        self.xmodule.graded = True
+        self.assertEqual(self.xmodule.max_score(), 100)
+
+        self.xmodule.graded = False
+        self.assertEqual(self.xmodule.max_score(), 0)
+
+