reset choice if not viewed and is suspended

Randomize module will select another choice if the problem is suspended
and hasn't been viewed by the student. If the student has already viewed
the problem then we can't reset in case they got the problem correct -
only a reset can assign another problem in this case.

common/lib/xmodule/xmodule/randomize_module.py

@@ -59,22 +59,30 @@ class RandomizeModule(RandomizeFields, XModule):
 
     def pick_choice(self, use_randrange=False, no_repeats=False,
                     suspended=None):
-        choices = self.get_choices(no_repeats=no_repeats, suspended=suspended)
         all_choices = self.get_choices()
         current_child = all_choices.get(self.choice)
+        suspended = suspended or []
         if current_child:
             cloc = current_child.location
-            if cloc.url() not in choices and cloc.name not in (suspended or []):
-                # child exists but is not in the list of choices. dont
-                # reset suspended problems otherwise students that passed will
-                # lose their grade.
+            viewed = self.has_viewed(cloc.url())
+            if not viewed and cloc.name in suspended:
+                # reset choice if problem has been suspended and student has
+                # yet to visit the problem. don't reset suspended problems that
+                # have been viewed otherwise students that passed will lose
+                # their grade.
+                log.warn("Problem %s has been suspended and student hasn't "
+                         "viewed it yet - resetting" % cloc.url())
                 self.choice = None
+            elif viewed and cloc.name in suspended:
+                log.warn("Problem %s has been suspended but student already "
+                         "viewed the problem - *NOT* resetting" % cloc.url())
         elif self.choice is not None:
             log.warn("Problem removed from course XML: %s" % self.choice)
             # current choice no longer exists in course XML - reset
             self.choice = None
 
         if self.choice is None:
+            choices = self.get_choices(no_repeats=no_repeats, suspended=suspended)
             num_choices = len(choices)
             # choose one based on the system seed, or randomly if that's not
             # available
@@ -112,9 +120,12 @@ class RandomizeModule(RandomizeFields, XModule):
             self.child_descriptor = None
             self.child = None
 
+    def has_viewed(self, choice):
+        return choice in self.history
+
     def get_choices(self, no_repeats=None, suspended=None):
         children = self.descriptor.get_children()
-        if self.choice is None and no_repeats:
+        if no_repeats:
             children = [c for c in children if c.location.url() not in
                         self.history]
         if suspended: