fix: The XBlock should work even when max_attempts is null

This change allows the XBlock to continue working in cases where max_attempts is
set to null. Currently Studio and LMS will throw an error in such a case due
to a number of places where max_attempts is compared to count_attempts without
testing for None first.

freetextresponse/tests/submitdisplay_class.json

@@ -1,7 +1,12 @@
 {
+    "empty_null_max": {
+        "max_attempts": null,
+        "count_attempts": 1, 
+        "result": ""
+    },
     "empty_zero_max": {
         "max_attempts": 0,
-        "count_attempts": 1, 
+        "count_attempts": 1,
         "result": ""
     },
     "empty_under_max": {

freetextresponse/tests/test_all.py

@@ -1,6 +1,7 @@
 """
 Module To Test FreeTextResponse XBlock
 """
+from datetime import datetime, timedelta
 from os import path
 import json
 import unittest
@@ -88,7 +89,7 @@ def test_generate_validation_message(self):
     def test_validate_field_data(self, **test_dict):
         """
         Checks classmethod validate_field_data
-        tests the instuctor values set in edit
+        tests the instructor values set in edit
         """
         test_data = TestData()
         test_data.weight = test_dict['weight']
@@ -324,6 +325,7 @@ def test_word_count_valid(self, **test_data):
     # Messages
     @ddt.data(
         # max_attempts, count_attempts, result
+        (None, 4, ''),
         (0, 4, ''),
         (1, 0, 'You have used 0 of 1 submission'),
         (3, 2, 'You have used 2 of 3 submissions'),
@@ -412,7 +414,7 @@ def test_get_submitted_message(
         Tests _get_submitted_message
         Returns a message to display to
         the user after they submit a
-        resopnse
+        response
         """
         self.xblock._word_count_valid = MagicMock(
             return_value=word_count_valid
@@ -497,12 +499,29 @@ def test_get_submitdisplay_class(self, **test_data):
             self.xblock._get_nodisplay_class()
         )
 
-    def test_submit(self):
+    @ddt.data(
+        ({'max_attempts': None, 'count_attempts': 1}, True),
+        ({'max_attempts': None, 'count_attempts': 3}, True),
+        ({'max_attempts': 0, 'count_attempts': 3}, True),
+        ({'max_attempts': 3, 'count_attempts': 2}, True),
+        ({'max_attempts': 3, 'count_attempts': 3}, False),
+        ({'due': None, 'graceperiod': None}, True),
+        ({'due': None, 'graceperiod': timedelta(hours=1)}, True),
+        ({'due': datetime.utcnow() + timedelta(hours=1), 'graceperiod': None}, True),
+        ({'due': datetime.utcnow() - timedelta(hours=1), 'graceperiod': None}, False),
+        ({'due': datetime.utcnow() - timedelta(hours=1), 'graceperiod': timedelta(hours=2)}, True),
+        ({'due': datetime.utcnow() - timedelta(hours=5), 'graceperiod': timedelta(hours=2)}, False),
+    )
+    @ddt.unpack
+    def test_submit(self, xblock_config, can_submit):
         # pylint: disable=protected-access
         """
-        Tests save_reponse results
+        Tests save_response results
         """
-        data = json.dumps({'student_answer': 'asdf'})
+        student_answer = 'asdf'
+        for key, value in xblock_config.items():
+            setattr(self.xblock, key, value)
+        data = json.dumps({'student_answer': student_answer})
         request = TestRequest()
         request.method = 'POST'
         request.body = data.encode('utf-8')
@@ -543,13 +562,27 @@ def test_submit(self):
             response.json_body['visibility_class'],
             self.xblock._get_indicator_visibility_class()
         )
+        self.assertEqual(
+            self.xblock.student_answer,
+            student_answer if can_submit else ''
+        )
 
-    def test_save_reponse(self):
+    @ddt.data(
+        ({'max_attempts': None, 'count_attempts': 1}, True),
+        ({'max_attempts': None, 'count_attempts': 3}, True),
+        ({'max_attempts': 0, 'count_attempts': 3}, True),
+        ({'max_attempts': 3, 'count_attempts': 3}, False)
+    )
+    @ddt.unpack
+    def test_save_response(self, xblock_config, can_save):
         # pylint: disable=protected-access
         """
-        Tests save_reponse results
+        Tests save_response results
         """
-        data = json.dumps({'student_answer': 'asdf'})
+        student_answer = 'asdf'
+        for key, value in xblock_config.items():
+            setattr(self.xblock, key, value)
+        data = json.dumps({'student_answer': student_answer})
         request = TestRequest()
         request.method = 'POST'
         request.body = data.encode('utf-8')
@@ -587,3 +620,7 @@ def test_save_reponse(self):
             response.json_body['visibility_class'],
             self.xblock._get_indicator_visibility_class()
         )
+        self.assertEqual(
+            self.xblock.student_answer,
+            student_answer if can_save else ''
+        )

freetextresponse/tests/validate_field_data.json

@@ -1,13 +1,13 @@
 {
-    "weight_attemps_negative": {
+    "weight_attempts_negative": {
         "weight": -1,
         "max_attempts": 1,
         "max_word_count": 1,
         "min_word_count": 1,
         "submitted_message": "s",
         "result": "Weight Attempts cannot be negative"
     },
-    "max_attemps_negative": {
+    "max_attempts_negative": {
         "weight": 0,
         "max_attempts": -1,
         "max_word_count": 1,

freetextresponse/views.py

@@ -74,7 +74,7 @@ def _get_nodisplay_class(self):
         Returns the css class for the submit button
         """
         result = ''
-        if self.max_attempts > 0 and self.count_attempts >= self.max_attempts:
+        if self.max_attempts and 0 < self.max_attempts <= self.count_attempts:
             result = 'nodisplay'
         return result
 
@@ -142,7 +142,7 @@ def _get_used_attempts_feedback(self):
         they have used if applicable
         """
         result = ''
-        if self.max_attempts > 0:
+        if self.max_attempts and self.max_attempts > 0:
             result = self.ngettext(
                 'You have used {count_attempts} of {max_attempts} submission',
                 'You have used {count_attempts} of {max_attempts} submissions',
@@ -206,7 +206,7 @@ def submit(self, data, suffix=''):
         Processes the user's submission
         """
         # Fails if the UI submit/save buttons were shut
-        # down on the previous sumbisson
+        # down on the previous submission
         if self._can_submit():
             self.student_answer = data['student_answer']
             # Counting the attempts and publishing a score
@@ -239,8 +239,8 @@ def save_reponse(self, data, suffix=''):
         Processes the user's save
         """
         # Fails if the UI submit/save buttons were shut
-        # down on the previous sumbisson
-        if self.max_attempts == 0 or self.count_attempts < self.max_attempts:
+        # down on the previous submission
+        if not self.max_attempts or self.count_attempts < self.max_attempts:
             self.student_answer = data['student_answer']
         result = {
             'status': 'success',
@@ -295,7 +295,7 @@ def _can_submit(self):
         """
         if self.is_past_due():
             return False
-        if self.max_attempts == 0:
+        if not self.max_attempts:
             return True
         if self.count_attempts < self.max_attempts:
             return True