Implement math.gcd in dart.

tests/lib/math/math_package_bigint_test.dart

+// Copyright (c) 2011, 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 math_test;
+import "package:expect/expect.dart";
+import 'dart:math';
+import 'package:math/math.dart';

[Lasse Reichstein Nielsen, 2014/08/20 12:17:02]

Test of package functionality should go in the package itself, so put this and
other tests in pkg/math/tests/.

The status file for that is pkg.status.

[srawlins, 2014/08/25 05:43:54]

Done.

+
+// See math_package_test.dart first.  This file contains only the tests that
+// need Bigint or would fail in dart2js compatibility mode.
+
+class MathPackageBigintTest {

[Lasse Reichstein Nielsen, 2014/08/20 12:17:02]

No need for a class here, or a testMain method, just make the function top-level
and call it directly from main.

Some old tests are using a class, but that's probably because the tests were
written before top-level functions were fully implemented.

[srawlins, 2014/08/25 05:43:54]

Done.

+  static void testGcdWithBigints() {
+    Expect.equals(pow(2, 63)*3, gcd(pow(2, 64)*3*5, pow(2,63)*3*7));
+    // 595056260442243647 is the first prime after 2**64 / 31.
+    Expect.equals(595056260442243647,
+      gcd(31*595056260442243647, 37*595056260442243647));
+  }
+
+  static testMain() {
+    testGcdWithBigints();
+  }
+}
+
+main() {
+  MathPackageBigintTest.testMain();
+}