Shuffle feature for multiple choice questions

CHANGELOG.rst

@@ -67,6 +67,9 @@ Blades: Add view for field type Dict in Studio. BLD-658.
 
 Blades: Refactor stub implementation of LTI Provider. BLD-601.
 
+LMS: multiple choice features: shuffle, answer-pool, targeted-feedback,
+choice name masking, submission timer
+
 Studio: Added ability to edit course short descriptions that appear on the course catalog page.
 
 LMS: In left accordion and progress page, due dates are now displayed in time

cms/djangoapps/contentstore/features/problem-editor.py

@@ -13,7 +13,7 @@
 PROBLEM_WEIGHT = "Problem Weight"
 RANDOMIZATION = 'Randomization'
 SHOW_ANSWER = "Show Answer"
-
+TIMER_BETWEEN_ATTEMPTS = "Timer Between Attempts"
 
 @step('I have created a Blank Common Problem$')
 def i_created_blank_common_problem(step):
@@ -44,6 +44,7 @@ def i_see_advanced_settings_with_values(step):
             [PROBLEM_WEIGHT, "", False],
             [RANDOMIZATION, "Never", False],
             [SHOW_ANSWER, "Finished", False],
+            [TIMER_BETWEEN_ATTEMPTS, "0", False]
         ])
 
 

common/lib/capa/capa/capa_problem.py

@@ -178,6 +178,14 @@ def __init__(self, problem_text, id, capa_system, state=None, seed=None):
         #   input_id string -> InputType object
         self.inputs = {}
 
+        # Run response late_transforms last (see MultipleChoiceResponse)
+        # Sort the responses to be in *_1 *_2 ... order.
+        responses = self.responders.values()
+        responses = sorted(responses, key=lambda resp: int(resp.id[resp.id.rindex('_') + 1:]))
+        for response in responses:
+            if hasattr(response, 'late_transforms'):
+                response.late_transforms(self)
+
         self.extracted_tree = self._extract_html(self.tree)
 
     def do_reset(self):
@@ -419,10 +427,84 @@ def get_answer_ids(self):
             answer_ids.append(results.keys())
         return answer_ids
 
+    def do_targeted_feedback(self, tree):
+        """
+        Implements the targeted-feedback=N in-place on  <multiplechoiceresponse> --
+        choice-level explanations shown to a student after submission.
+        Does nothing if there is no targeted-feedback attribute.
+        """
+        for mult_choice_response in tree.xpath('//multiplechoiceresponse[@targeted-feedback]'):
+            # Note that the modifications has been done, avoiding problems if called twice.
+            if hasattr(self, 'has_targeted'):
+                continue
+            self.has_targeted = True  # pylint: disable=W0201
+
+            show_explanation = mult_choice_response.get('targeted-feedback') == 'alwaysShowCorrectChoiceExplanation'
+
+            # Grab the first choicegroup (there should only be one within each <multiplechoiceresponse> tag)
+            choicegroup = mult_choice_response.xpath('./choicegroup[@type="MultipleChoice"]')[0]
+            choices_list = list(choicegroup.iter('choice'))
+
+            # Find the student answer key that matches our <choicegroup> id
+            student_answer = self.student_answers.get(choicegroup.get('id'))
+            expl_id_for_student_answer = None
+
+            # Keep track of the explanation-id that corresponds to the student's answer
+            # Also, keep track of the solution-id
+            solution_id = None
+            for choice in choices_list:
+                if choice.get('name') == student_answer:
+                    expl_id_for_student_answer = choice.get('explanation-id')
+                if choice.get('correct') == 'true':
+                    solution_id = choice.get('explanation-id')
+
+            # Filter out targetedfeedback that doesn't correspond to the answer the student selected
+            # Note: following-sibling will grab all following siblings, so we just want the first in the list
+            targetedfeedbackset = mult_choice_response.xpath('./following-sibling::targetedfeedbackset')
+            if len(targetedfeedbackset) != 0:
+                targetedfeedbackset = targetedfeedbackset[0]
+                targetedfeedbacks = targetedfeedbackset.xpath('./targetedfeedback')
+                for targetedfeedback in targetedfeedbacks:
+                    # Don't show targeted feedback if the student hasn't answer the problem
+                    # or if the target feedback doesn't match the student's (incorrect) answer
+                    if not self.done or targetedfeedback.get('explanation-id') != expl_id_for_student_answer:
+                        targetedfeedbackset.remove(targetedfeedback)
+
+            # Do not displace the solution under these circumstances
+            if not show_explanation or not self.done:
+                continue
+
+            # The next element should either be <solution> or <solutionset>
+            next_element = targetedfeedbackset.getnext()
+            parent_element = tree
+            solution_element = None
+            if next_element is not None and next_element.tag == 'solution':
+                solution_element = next_element
+            elif next_element is not None and next_element.tag == 'solutionset':
+                solutions = next_element.xpath('./solution')
+                for solution in solutions:
+                    if solution.get('explanation-id') == solution_id:
+                        parent_element = next_element
+                        solution_element = solution
+
+            # If could not find the solution element, then skip the remaining steps below
+            if solution_element is None:
+                continue
+
+            # Change our correct-choice explanation from a "solution explanation" to within
+            # the set of targeted feedback, which means the explanation will render on the page
+            # without the student clicking "Show Answer" or seeing a checkmark next to the correct choice
+            parent_element.remove(solution_element)
+
+            # Add our solution instead to the targetedfeedbackset and change its tag name
+            solution_element.tag = 'targetedfeedback'
+            targetedfeedbackset.append(solution_element)
+
     def get_html(self):
         """
         Main method called externally to get the HTML to be rendered for this capa Problem.
         """
+        self.do_targeted_feedback(self.tree)
         html = contextualize_text(etree.tostring(self._extract_html(self.tree)), self.context)
         return html
 

common/lib/capa/capa/customrender.py

@@ -11,6 +11,7 @@
 import logging
 import re
 
+from cgi import escape as cgi_escape
 from lxml import etree
 import xml.sax.saxutils as saxutils
 from .registry import TagRegistry
@@ -98,3 +99,42 @@ def get_html(self):
         return etree.XML(html)
 
 registry.register(SolutionRenderer)
+
+#-----------------------------------------------------------------------------
+
+
+class TargetedFeedbackRenderer(object):
+    """
+    A targeted feedback is just a <span>...</span> that is used for displaying an
+    extended piece of feedback to students if they incorrectly answered a question.
+    """
+    tags = ['targetedfeedback']
+
+    def __init__(self, system, xml):
+        self.system = system
+        self.xml = xml
+
+    def get_html(self):
+        """
+        Return the contents of this tag, rendered to html, as an etree element.
+        """
+        html = '<section class="targeted-feedback-span"><span>{}</span></section>'.format(etree.tostring(self.xml))
+        try:
+            xhtml = etree.XML(html)
+        except Exception as err:  # pylint: disable=broad-except
+            if self.system.DEBUG:
+                msg = """
+                    <html>
+                      <div class="inline-error">
+                        <p>Error {err}</p>
+                        <p>Failed to construct targeted feedback from <pre>{html}</pre></p>
+                      </div>
+                    </html>
+                """.format(err=cgi_escape(err), html=cgi_escape(html))
+                log.error(msg)
+                return etree.XML(msg)
+            else:
+                raise
+        return xhtml
+
+registry.register(TargetedFeedbackRenderer)