Fix utility function in smoke, add tests for it.

pkg/smoke/lib/src/common.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// Some common utilities used by other libraries in this package.
 library smoke.src.common;
 
 import 'package:smoke/smoke.dart' as smoke show isSubclassOf;
 
 /// Returns [input] adjusted to be within [min] and [max] length. Truncating it
@@ skipping 70 matching lines @@
 /// Shallow comparison of two lists.
 bool compareLists(List a, List b, {bool unordered: false}) {
   if (a == null && b != null) return false;
   if (a != null && b == null) return false;
   if (a.length != b.length) return false;
   if (unordered) {
     var bSet = new Set()..addAll(b);
     for (int i = 0; i < a.length; i++) {
       if (!bSet.contains(a[i])) return false;
     }
+
+    var aSet = new Set()..addAll(a);
+    for (int i = 0; i < b.length; i++) {
+      if (!aSet.contains(b[i])) return false;
+    }

[vicb, 2014/07/13 09:55:02]

I think that the code is still not right.

[1 1 2 2 2] would still equal [1 1 1 2 2]

(As a side note it would be more efficient to compare Set vs Set rather than
compare Set vs List - we do build both aSet and bSet. However is is n/a as the
code seems to be incorrect)

[justinfagnani, 2014/07/14 17:20:19]

A Set is not going to work here, you need two maps of item->count. Calculate the
counts for each list, then compare the counts.

[Siggi Cherem (dart-lang), 2014/07/14 19:48:57]

<facepalm> ... Ok I updated this again, hopefully this is better now.

The reality is that this code is only used for the debug_static configuration,
which is just used while developing code generators to verify that a static
configuration contains everything you expect you'd get by comparing it with the
results from using mirrors (ignoring the order of some operations).

Most operations return lists, but in reality they are actually ordered-sets. So
these issues with duplicates were never a concern there. We could rename this as
compareListsContents and just use Set equality and we'd be good too.

   } else {
     for (int i = 0; i < a.length; i++) {
       if (a[i] != b[i]) return false;
     }
   }
   return true;
 }
 
 /// Shallow comparison of two maps.
 bool compareMaps(Map a, Map b) {
   if (a == null && b != null) return false;
   if (a != null && b == null) return false;
   if (a.length != b.length) return false;
   for (var k in a.keys) {
     if (!b.containsKey(k) || a[k] != b[k]) return false;
   }
   return true;
 }