[WWcvs] pg: Fixed error in testing is a union is reduced (didn't test if sets

[dpvc v. a. <we...@ma...>]

Log Message:
-----------
Fixed error in testing is a union is reduced (didn't test if sets
within a union were reduced properly).

Modified Files:
--------------
    pg/lib/Value:
        AnswerChecker.pm

Revision Data
-------------
Index: AnswerChecker.pm
===================================================================
RCS file: /webwork/cvs/system/pg/lib/Value/AnswerChecker.pm,v
retrieving revision 1.57
retrieving revision 1.58
diff -Llib/Value/AnswerChecker.pm -Llib/Value/AnswerChecker.pm -u -r1.57 -r1.58
--- lib/Value/AnswerChecker.pm
+++ lib/Value/AnswerChecker.pm
@@ -257,12 +257,11 @@
     my @S = $student->sort->value;
     foreach my $i (0..$#R) {
       return "Your$nth union can be written in a simpler form"
-	unless $R[$i] == $S[$i];
+	unless $R[$i] == $S[$i] && $R[$i]->length == $S[$i]->length;
     }
-  } elsif ($student->type eq 'Set') {
-    my $reduced = $student->reduce;
+  } elsif ($student->type eq 'Set' && $student->length >= 2) {
     return "Your$nth set should have no redundant elements"
-      unless $reduced->length == $student->length;
+      unless $student->reduce->length == $student->length;
   }
   return;
 }