Test closed world model after deserialization.

tests/compiler/dart2js/serialization_test.dart

 // Copyright (c) 2015, 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.
 
 library dart2js.serialization_test;
 
 import 'dart:io';
 import 'memory_compiler.dart';
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/commandline_options.dart';
@@ skipping 153 matching lines @@
   for (int i = list2.length; i < list1.length; i++) {
     throw
         'Missing equivalent for element '
         '#$i ${list1.elementAt(i)} in `${property}` on $object1.\n'
         '`${property}` on $object1:\n ${list1.join('\n ')}\n'
         '`${property}` on $object2:\n ${list2.join('\n ')}';
   }
   return true;
 }
 
-/// Check equivalence of the two iterables, [set1] and [set1], as sets using
-/// [elementEquivalence] to compute the pair-wise equivalence.
+/// Computes the set difference between [set1] and [set2] using
+/// [elementEquivalence] to determine element equivalence.
 ///
-/// Uses [object1], [object2] and [property] to provide context for failures.
-bool checkSetEquivalence(
-    var object1,
-    var object2,
-    String property,
+/// Elements both in [set1] and [set2] are added to [common], elements in [set1]
+/// but not in [set2] are added to [unfound], and the set of elements in [set2]
+/// but not in [set1] are returned.
+Set computeSetDifference(
     Iterable set1,
     Iterable set2,
-    bool sameElement(a, b)) {
-  List common = [];
-  List unfound = [];
+    List common,
+    List unfound,
+    [bool sameElement(a, b) = equality]) {
+  // TODO(johnniwinther): Avoid the quadratic cost here. Some ideas:
+  // - convert each set to a list and sort it first, then compare by walking
+  // both lists in parallel
+  // - map each element to a canonical object, create a map containing those
+  // mappings, use the mapped sets to compare (then operations like
+  // set.difference would work)
   Set remaining = set2.toSet();
   for (var element1 in set1) {
     bool found = false;
     for (var element2 in remaining) {
       if (sameElement(element1, element2)) {
         found = true;
         remaining.remove(element2);
         break;
       }
     }
     if (found) {
       common.add(element1);
     } else {
       unfound.add(element1);
     }
   }
+  return remaining;
+}
+
+/// Check equivalence of the two iterables, [set1] and [set1], as sets using
+/// [elementEquivalence] to compute the pair-wise equivalence.
+///
+/// Uses [object1], [object2] and [property] to provide context for failures.
+bool checkSetEquivalence(
+    var object1,
+    var object2,
+    String property,
+    Iterable set1,
+    Iterable set2,
+    bool sameElement(a, b)) {
+  List common = [];
+  List unfound = [];
+  Set remaining =
+      computeSetDifference(set1, set2, common, unfound, sameElement);
   if (unfound.isNotEmpty || remaining.isNotEmpty) {
     String message =
         "Set mismatch for `$property` on $object1 vs $object2: \n"
         "Common:\n ${common.join('\n ')}\n"
         "Unfound:\n ${unfound.join('\n ')}\n"
         "Extra: \n ${remaining.join('\n ')}";
     throw message;
   }
   return true;
 }
@@ skipping 652 matching lines @@
   void visitPrefixElement(PrefixElement element1, PrefixElement element2) {
     check(
         element1, element2, 'isDeferred',
         element1.isDeferred, element2.isDeferred);
     checkElementIdentities(
         element1, element2, 'importedLibrary',
         element1.deferredImport, element2.deferredImport);
     // TODO(johnniwinther): Check members.
   }
 }