Fix hash code tests to be non-flaky.

tests/compiler/dart2js_extra/hash_code_test.dart

Index: tests/compiler/dart2js_extra/hash_code_test.dart
diff --git a/tests/compiler/dart2js_extra/hash_code_test.dart b/tests/compiler/dart2js_extra/hash_code_test.dart
index bf7aed523dd0f6e14d9239e8cf023769c95f25e9..0c5c4b3a911a5219687bcebc13819cb38ec3077e 100644
--- a/tests/compiler/dart2js_extra/hash_code_test.dart
+++ b/tests/compiler/dart2js_extra/hash_code_test.dart
@@ -17,25 +17,28 @@ class Hasher {
 // local x.hashCode calls might be optimized.
 var hash = new Hasher().hash;
 
-check(value1, value2) {
+check(value1, value2, {identityHashCode}) {

[ahe, 2013/06/04 13:19:49]

bool identityHashCode: false

   var h1 = hash(value1);
   var h2 = hash(value2);
-
   Expect.isTrue(h1 is int);
   Expect.isTrue(h2 is int);
-  Expect.isFalse(h1 == h2);
-
-  // We expect that the hash function is reasonable quality - there are some
-  // difference in the low bits.
-  Expect.isFalse((h1 & 0xf) == (h2 & 0xf));
 
   // Quality check - the values should be SMIs for efficient arithmetic.
   Expect.equals((h1 & 0x3fffffff), h1);
   Expect.equals((h2 & 0x3fffffff), h2);
+
+  // If we're checking the (randomized) identity hash code function,
+  // we cannot guarantee anything about the actual hash code values.
+  if (identityHashCode) return;

[ahe, 2013/06/04 13:19:49]

Otherwise this will fail in checked mode.

+
+  // We expect that the hash function is reasonable quality - there
+  // are some difference in the low bits.
+  Expect.isFalse(h1 == h2);
+  Expect.isFalse((h1 & 0xf) == (h2 & 0xf));
 }
 
 bools() {
-  check(true, false);
+  check(true, false, identityHashCode: false);
 
   Expect.equals(true.hashCode, hash(true));   // First can be optimized.
   Expect.equals(false.hashCode, hash(false));
@@ -44,7 +47,7 @@ bools() {
 ints() {
   var i1 = 100;
   var i2 = 101;
-  check(i1, i2);
+  check(i1, i2, identityHashCode: false);
   Expect.equals(i1.hashCode, hash(i1));
   Expect.equals(i2.hashCode, hash(i2));
 }
@@ -52,7 +55,7 @@ ints() {
 lists() {
   var list1 = [];
   var list2 = [];
-  check(list1, list2);
+  check(list1, list2, identityHashCode: true);
 
   Expect.equals(list1.hashCode, hash(list1));
   Expect.equals(list2.hashCode, hash(list2));
@@ -62,9 +65,9 @@ strings() {
   var str1 = 'a';
   var str2 = 'b';
   var str3 = 'c';
-  check(str1, str2);
-  check(str1, str3);
-  check(str2, str3);
+  check(str1, str2, identityHashCode: false);
+  check(str1, str3, identityHashCode: false);
+  check(str2, str3, identityHashCode: false);
 
   Expect.equals(str1.hashCode, hash(str1));
   Expect.equals(str2.hashCode, hash(str2));