Add isFinite getter to num.

tests/corelib/nan_infinity_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.
 
 import "package:expect/expect.dart";
 
 // Dart test program for testing NaN and Infinity.
 
 void main() {
+  // Sanity tests.
+  Expect.isFalse(1.5.isNaN);
+  Expect.isFalse(1.5.isInfinite);
+  Expect.isTrue(1.5.isFinite);
+  Expect.isFalse(1.5.isNegative);
+  Expect.isTrue((-1.5).isNegative);
+  Expect.isFalse(0.0.isNegative);
+  Expect.isTrue((-0.0).isNegative);
+  Expect.isTrue((-0.0).isFinite);
+
+  Expect.isFalse(1.isNaN);
+  Expect.isFalse(1.isInfinite);
+  Expect.isTrue(1.isFinite);
+  Expect.isFalse(1.isNegative);
+  Expect.isTrue((-1).isNegative);
+
+  // Test that predicates give the correct result.
   Expect.isTrue(double.NAN.isNaN);
   Expect.isFalse(double.NAN.isInfinite);
+  Expect.isFalse(double.NAN.isFinite);
+  Expect.isFalse(double.NAN.isNegative);
+  Expect.isFalse((-double.NAN).isNegative);
+
   Expect.isFalse(double.INFINITY.isNaN);
   Expect.isTrue(double.INFINITY.isInfinite);
+  Expect.isFalse(double.INFINITY.isFinite);
+  Expect.isFalse(double.INFINITY.isNegative);
+  Expect.isTrue((-double.INFINITY).isNegative);
+
   Expect.isFalse(double.NEGATIVE_INFINITY.isNaN);
   Expect.isTrue(double.NEGATIVE_INFINITY.isInfinite);
+  Expect.isFalse(double.NEGATIVE_INFINITY.isFinite);
+  Expect.isTrue(double.NEGATIVE_INFINITY.isNegative);
+  Expect.isFalse((-double.NEGATIVE_INFINITY).isNegative);
+
+  // Test toString.
   Expect.equals("NaN", double.NAN.toString());
   Expect.equals("Infinity", double.INFINITY.toString());
   Expect.equals("-Infinity", double.NEGATIVE_INFINITY.toString());
-  Expect.isFalse(double.NAN == double.NAN);
+
+  // Test identities.
+  Expect.isTrue(identical(double.NAN, double.NAN));  /// 01: ok
+  Expect.isTrue(identical(double.INFINITY, double.INFINITY));
+  Expect.isTrue(identical(double.NEGATIVE_INFINITY, double.NEGATIVE_INFINITY));
+  Expect.isFalse(identical(double.NAN, double.INFINITY));
+  Expect.isFalse(identical(double.NAN, double.NEGATIVE_INFINITY));
+  Expect.isFalse(identical(double.INFINITY, double.NEGATIVE_INFINITY));
+  Expect.isTrue(identical(double.NAN, -double.NAN));  /// 01: continued
+  Expect.isTrue(identical(double.INFINITY, -double.NEGATIVE_INFINITY));
+  Expect.isTrue(identical(double.NEGATIVE_INFINITY, -double.INFINITY));
+
+  // Test equalities
   Expect.isTrue(double.INFINITY == double.INFINITY);
   Expect.isTrue(double.NEGATIVE_INFINITY == double.NEGATIVE_INFINITY);
+  Expect.isFalse(double.INFINITY == double.NEGATIVE_INFINITY);
+  Expect.isFalse(double.NEGATIVE_INFINITY == double.INFINITY);
+  Expect.isFalse(double.NAN == double.NAN);
+  Expect.isFalse(double.NAN == double.INFINITY);
+  Expect.isFalse(double.NAN == double.NEGATIVE_INFINITY);
+  Expect.isFalse(double.INFINITY == double.NAN);
+  Expect.isFalse(double.NEGATIVE_INFINITY == double.NAN);
+
+  // Test relational order.
   Expect.isFalse(double.NAN < double.NAN);
   Expect.isFalse(double.NAN < double.INFINITY);
   Expect.isFalse(double.NAN < double.NEGATIVE_INFINITY);
   Expect.isFalse(double.NAN > double.NAN);
   Expect.isFalse(double.NAN > double.INFINITY);
   Expect.isFalse(double.NAN > double.NEGATIVE_INFINITY);
-  Expect.isFalse(double.NAN == double.NAN);
-  Expect.isFalse(double.NAN == double.INFINITY);
-  Expect.isFalse(double.NAN == double.NEGATIVE_INFINITY);
   Expect.isFalse(double.INFINITY < double.NAN);
   Expect.isFalse(double.NEGATIVE_INFINITY < double.NAN);
   Expect.isFalse(double.INFINITY > double.NAN);
   Expect.isFalse(double.NEGATIVE_INFINITY > double.NAN);
-  Expect.isFalse(double.INFINITY == double.NAN);
-  Expect.isFalse(double.NEGATIVE_INFINITY == double.NAN);
+  Expect.isTrue(double.INFINITY > double.NEGATIVE_INFINITY);
+  Expect.isFalse(double.INFINITY < double.NEGATIVE_INFINITY);
+
+  // NaN is contagious.
   Expect.isTrue((3.0 * double.NAN).isNaN);
-  Expect.isTrue(double.INFINITY > double.NEGATIVE_INFINITY);
+  Expect.isTrue((3.0 + double.NAN).isNaN);
+  Expect.isTrue((-double.NAN).isNaN);
 }