MDL-44980 quiz statistics report : break down by variants failing

when there has only been one variant seen.

mod/quiz/report/statistics/tests/fixtures/questions03.csv

@@ -0,0 +1,2 @@
+slot,type,which,cat,mark
+1,calculatedsimple,sumwithvariants,maincat,1

mod/quiz/report/statistics/tests/fixtures/quizzes.csv

@@ -2,3 +2,4 @@ testnumber,preferredbehaviour
 00,deferredfeedback
 01,interactive
 02,interactive
+03,deferredfeedback

mod/quiz/report/statistics/tests/fixtures/responsecounts03.csv

@@ -0,0 +1,2 @@
+slot,variant,modelresponse,actualresponse,totalcount
+1,4,"{a} + {b} (±0.01 Relative)",19.4,1

mod/quiz/report/statistics/tests/fixtures/steps03.csv

@@ -0,0 +1,2 @@
+quizattempt,firstname,lastname,responses.1.answer,variants.1
+1,John,Jones,19.4,4

question/classes/statistics/questions/all_calculated_for_qubaid_condition.php

@@ -136,20 +136,6 @@ public function get_all_slots() {
         return array_keys($this->questionstats);
     }
 
-    /**
-     * Array of variants of one randomly selected question that have appeared in the attempt data.
-     *
-     * @param int $questionid The id for the sub question.
-     * @return int[] The variant nos.
-     */
-    public function get_variants_for_subq($questionid) {
-        if (count($this->subquestionstats[$questionid]->variantstats) > 1) {
-            return array_keys($this->subquestionstats[$questionid]->variantstats);
-        } else {
-            return false;
-        }
-    }
-
     /**
      * Get position stats instance for a slot and optional variant no.
      *
@@ -351,7 +337,7 @@ protected function all_subq_variants_for_one_slot($slot) {
         $toreturn = array();
         $displayorder = 1;
         foreach ($this->for_slot($slot)->get_sub_question_ids() as $subqid) {
-            if ($variants = $this->get_variants_for_subq($subqid)) {
+            if ($variants = $this->for_subq($subqid)->get_variants()) {
                 foreach ($variants as $variant) {
                     $toreturn[] = $this->make_new_subq_stat_for($displayorder, $slot, $subqid, $variant);
                 }
@@ -406,7 +392,7 @@ protected function all_subq_and_variant_stats_for_slot($slot, $limited) {
             $displaynumber = 1;
             foreach ($this->for_slot($slot)->get_sub_question_ids() as $subqid) {
                 $toreturn[] = $this->make_new_subq_stat_for($displaynumber, $slot, $subqid);
-                if ($variants = $this->get_variants_for_subq($subqid)) {
+                if ($variants = $this->for_subq($subqid)->get_variants()) {
                     foreach ($variants as $variant) {
                         $toreturn[] = $this->make_new_subq_stat_for($displaynumber, $slot, $subqid, $variant);
                     }

question/classes/statistics/questions/calculated.php

@@ -230,7 +230,7 @@ public function cache($qubaids) {
         }
         $DB->insert_record('question_statistics', $toinsert, false);
 
-        if (count($this->variantstats) > 1) {
+        if ($this->get_variants()) {
             foreach ($this->variantstats as $variantstat) {
                 $variantstat->cache($qubaids);
             }
@@ -276,7 +276,7 @@ public function get_sub_question_ids() {
      */
     public function get_variants() {
         $variants = array_keys($this->variantstats);
-        if (count($variants) > 1) {
+        if (count($variants) > 1 || reset($variants) != 1) {
             return $variants;
         } else {
             return array();

question/classes/statistics/questions/calculator.php

@@ -161,7 +161,7 @@ public function calculate($qubaids) {
                 $this->stats->for_subq($qid)->question = $subquestion;
                 $this->stats->for_subq($qid)->randomguessscore = $this->get_random_guess_score($subquestion);
 
-                if ($variants = $this->stats->get_variants_for_subq($qid)) {
+                if ($variants = $this->stats->for_subq($qid)->get_variants()) {
                     foreach ($variants as $variant) {
                         $this->stats->for_subq($qid, $variant)->question = $subquestion;
                         $this->stats->for_subq($qid, $variant)->randomguessscore = $this->get_random_guess_score($subquestion);