strip the answer when validating the min_characters

mentoring/answer.py

@@ -52,7 +52,7 @@ class AnswerBlock(LightChild):
     default_from = String(help="If specified, the name of the answer to get the default value from",
                           default=None, scope=Scope.content)
     min_characters = Integer(help="Minimum number of characters allowed for the answer",
-                             scope=Scope.content)
+                             default=0, scope=Scope.content)
 
     @lazy
     def student_input(self):
@@ -110,7 +110,7 @@ class AnswerBlock(LightChild):
     def completed(self):
         answer_length_ok = self.student_input
         if self.min_characters > 0:
-            answer_length_ok = len(self.student_input) >= self.min_characters
+            answer_length_ok = len(self.student_input.strip()) >= self.min_characters
 
         return bool(self.read_only or answer_length_ok)
 

mentoring/mrq.py

@@ -43,8 +43,10 @@ class MRQBlock(QuestionnaireAbstractBlock):
     An XBlock used to ask multiple-response questions
     """
     student_choices = List(help="Last submissions by the student", default=[], scope=Scope.user_state)
-    max_attempts = Integer(help="Number of max attempts for this questions", scope=Scope.content)
-    num_attempts = Integer(help="Number of attempts a user has answered for this questions", scope=Scope.user_state)
+    max_attempts = Integer(help="Number of max attempts for this questions", default=0,
+                           scope=Scope.content)
+    num_attempts = Integer(help="Number of attempts a user has answered for this questions",
+                           default=0, scope=Scope.user_state)
 
     # TODO REMOVE THIS, ONLY NEEDED FOR LIGHTCHILDREN
     @classmethod

mentoring/public/js/answer.js

@@ -2,7 +2,8 @@ function AnswerBlock(runtime, element) {
     return {
         submit: function() {
             var input = $(':input', element),
-                answer_length = input.val().length,
+                input_value = input.val().replace(/^\s+|\s+$/gm,''),
+                answer_length = input_value.length,
                 data = input.data();
 
             if (_.isNumber(data.min_characters) &&