Add Set.union, Set.difference. Change Set methods to expect Set.

tests/corelib/set_test.dart

Index: tests/corelib/set_test.dart
diff --git a/tests/corelib/set_test.dart b/tests/corelib/set_test.dart
index 3be91d50ab5cbfd1547cbaf619d7879e56f76b7d..940e4271d0940f4d2cd3e419c1d66b7c5a13473e 100644
--- a/tests/corelib/set_test.dart
+++ b/tests/corelib/set_test.dart
@@ -11,15 +11,15 @@ void testMain(Set create()) {
   Expect.equals(0, set.length);
   set.add(1);
   Expect.equals(1, set.length);
-  Expect.equals(true, set.contains(1));
+  Expect.isTrue(set.contains(1));
 
   set.add(1);
   Expect.equals(1, set.length);
-  Expect.equals(true, set.contains(1));
+  Expect.isTrue(set.contains(1));
 
   set.remove(1);
   Expect.equals(0, set.length);
-  Expect.equals(false, set.contains(1));
+  Expect.isFalse(set.contains(1));
 
   for (int i = 0; i < 10; i++) {
     set.add(i);
@@ -27,13 +27,13 @@ void testMain(Set create()) {
 
   Expect.equals(10, set.length);
   for (int i = 0; i < 10; i++) {
-    Expect.equals(true, set.contains(i));
+    Expect.isTrue(set.contains(i));
   }
 
   Expect.equals(10, set.length);
 
   for (int i = 10; i < 20; i++) {
-    Expect.equals(false, set.contains(i));
+    Expect.isFalse(set.contains(i));
   }
 
   // Test Set.forEach.
@@ -45,8 +45,8 @@ void testMain(Set create()) {
   set.forEach(testForEach);
   Expect.equals(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1, sum);
 
-  Expect.equals(true, set.isSubsetOf(set));
-  Expect.equals(true, set.containsAll(set));
+  Expect.isTrue(set.isSubsetOf(set));
+  Expect.isTrue(set.containsAll(set));
 
   // Test Set.map.
   testMap(int val) {
@@ -56,16 +56,16 @@ void testMain(Set create()) {
   Set mapped = set.map(testMap).toSet();
   Expect.equals(10, mapped.length);
 
-  Expect.equals(true, mapped.contains(0));
-  Expect.equals(true, mapped.contains(1));
-  Expect.equals(true, mapped.contains(4));
-  Expect.equals(true, mapped.contains(9));
-  Expect.equals(true, mapped.contains(16));
-  Expect.equals(true, mapped.contains(25));
-  Expect.equals(true, mapped.contains(36));
-  Expect.equals(true, mapped.contains(49));
-  Expect.equals(true, mapped.contains(64));
-  Expect.equals(true, mapped.contains(81));
+  Expect.isTrue(mapped.contains(0));
+  Expect.isTrue(mapped.contains(1));
+  Expect.isTrue(mapped.contains(4));
+  Expect.isTrue(mapped.contains(9));
+  Expect.isTrue(mapped.contains(16));
+  Expect.isTrue(mapped.contains(25));
+  Expect.isTrue(mapped.contains(36));
+  Expect.isTrue(mapped.contains(49));
+  Expect.isTrue(mapped.contains(64));
+  Expect.isTrue(mapped.contains(81));
 
   sum = 0;
   set.forEach(testForEach);
@@ -85,59 +85,76 @@ void testMain(Set create()) {
 
   Expect.equals(5, filtered.length);
 
-  Expect.equals(true, filtered.contains(0));
-  Expect.equals(true, filtered.contains(2));
-  Expect.equals(true, filtered.contains(4));
-  Expect.equals(true, filtered.contains(6));
-  Expect.equals(true, filtered.contains(8));
+  Expect.isTrue(filtered.contains(0));
+  Expect.isTrue(filtered.contains(2));
+  Expect.isTrue(filtered.contains(4));
+  Expect.isTrue(filtered.contains(6));
+  Expect.isTrue(filtered.contains(8));
 
   sum = 0;
   filtered.forEach(testForEach);
   Expect.equals(1 + 3 + 5 + 7 + 9, sum);
 
-  Expect.equals(true, set.containsAll(filtered));
-  Expect.equals(true, filtered.isSubsetOf(set));
+  Expect.isTrue(set.containsAll(filtered));
+  Expect.isTrue(filtered.isSubsetOf(set));
 
   // Test Set.every.
   testEvery(int val) {
     return (val < 10);
   }
 
-  Expect.equals(true, set.every(testEvery));
-  Expect.equals(true, filtered.every(testEvery));
+  Expect.isTrue(set.every(testEvery));
+  Expect.isTrue(filtered.every(testEvery));
 
   filtered.add(10);
-  Expect.equals(false, filtered.every(testEvery));
+  Expect.isFalse(filtered.every(testEvery));
 
   // Test Set.some.
   testSome(int val) {
     return (val == 4);
   }
 
-  Expect.equals(true, set.any(testSome));
-  Expect.equals(true, filtered.any(testSome));
+  Expect.isTrue(set.any(testSome));
+  Expect.isTrue(filtered.any(testSome));
   filtered.remove(4);
-  Expect.equals(false, filtered.any(testSome));
+  Expect.isFalse(filtered.any(testSome));
 
   // Test Set.intersection.
   Set intersection = set.intersection(filtered);
-  Expect.equals(true, set.contains(0));
-  Expect.equals(true, set.contains(2));
-  Expect.equals(true, set.contains(6));
-  Expect.equals(true, set.contains(8));
-  Expect.equals(false, intersection.contains(1));
-  Expect.equals(false, intersection.contains(3));
-  Expect.equals(false, intersection.contains(4));
-  Expect.equals(false, intersection.contains(5));
-  Expect.equals(false, intersection.contains(7));
-  Expect.equals(false, intersection.contains(9));
-  Expect.equals(false, intersection.contains(10));
+  Expect.isTrue(set.contains(0));
+  Expect.isTrue(set.contains(2));
+  Expect.isTrue(set.contains(6));
+  Expect.isTrue(set.contains(8));
+  Expect.isFalse(intersection.contains(1));
+  Expect.isFalse(intersection.contains(3));
+  Expect.isFalse(intersection.contains(4));
+  Expect.isFalse(intersection.contains(5));
+  Expect.isFalse(intersection.contains(7));
+  Expect.isFalse(intersection.contains(9));
+  Expect.isFalse(intersection.contains(10));
   Expect.equals(4, intersection.length);
 
-  Expect.equals(true, set.containsAll(intersection));
-  Expect.equals(true, filtered.containsAll(intersection));
-  Expect.equals(true, intersection.isSubsetOf(set));
-  Expect.equals(true, intersection.isSubsetOf(filtered));
+  Expect.isTrue(set.containsAll(intersection));
+  Expect.isTrue(filtered.containsAll(intersection));
+  Expect.isTrue(intersection.isSubsetOf(set));
+  Expect.isTrue(intersection.isSubsetOf(filtered));
+
+  // Test Set.union.
+  Set twice = create()..addAll([0, 2, 4, 6, 8, 10, 12, 14]);
+  Set thrice = create()..addAll([0, 3, 6, 9, 12, 15]);
+  Set union = twice.union(thrice);
+  Expect.equals(11, union.length);
+  for (int i = 0; i < 16; i++) {
+    Expect.equals(i.isEven || (i % 3) == 0, union.contains(i));
+  }
+
+  // Test Set.difference.
+  Set difference = twice.difference(thrice);
+  Expect.equals(5, difference.length);
+  for (int i = 0; i < 16; i++) {
+    Expect.equals(i.isEven && (i % 3) != 0, difference.contains(i));
+  }
+  Expect.isTrue(twice.difference(thrice).difference(twice).isEmpty);
 
   // Test Set.addAll.
   List list = new List.fixedLength(10);
@@ -147,17 +164,17 @@ void testMain(Set create()) {
   set.addAll(list);
   Expect.equals(20, set.length);
   for (int i = 0; i < 20; i++) {
-    Expect.equals(true, set.contains(i));
+    Expect.isTrue(set.contains(i));
   }
 
   // Test Set.removeAll
   set.removeAll(list);
   Expect.equals(10, set.length);
   for (int i = 0; i < 10; i++) {
-    Expect.equals(true, set.contains(i));
+    Expect.isTrue(set.contains(i));
   }
   for (int i = 10; i < 20; i++) {
-    Expect.equals(false, set.contains(i));
+    Expect.isFalse(set.contains(i));
   }
 
   // Test Set.clear.