Allow a NumberFormat to be passed a currency name/symbol at creation

pkg/intl/test/number_format_test.dart

 /**
  * Copyright (c) 2012, 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 number_format_test;
 
 import 'package:unittest/unittest.dart';
 import 'package:intl/number_symbols_data.dart';
@@ skipping 76 matching lines @@
     }
   });
 
   test('Exponential form', () {
     var number = new NumberFormat("#.###E0");
     for (var x in testExponential.keys) {
       var formatted = number.format(testExponential[x]);
       expect(formatted, x);
     }
   });
+
+  test('Explicit currency name', () {
+    var amount = 1000000.32;
+    var usConvention = new NumberFormat.currencyPattern('en_US', '€');
+    var formatted = usConvention.format(amount);
+    expect(formatted, '€1,000,000.32');
+    var swissConvention = new NumberFormat.currencyPattern('de_CH', r'$');
+    formatted = swissConvention.format(amount);
+    var nbsp = new String.fromCharCode(0xa0);
+    expect(formatted, r"$" + nbsp + "1'000'000.32");
+
+    /// Verify we can leave off the currency and it gets filled in.
+    var plainSwiss = new NumberFormat.currencyPattern('de_CH');
+    formatted = plainSwiss.format(amount);
+    expect(formatted, r"CHF" + nbsp + "1'000'000.32");
+
+    // Verify that we can pass null in order to specify the currency symbol
+    // but use the default locale.
+    var defaultLocale = new NumberFormat.currencyPattern(null, 'Smurfs');
+    formatted = defaultLocale.format(amount);
+    // We don't know what the exact format will be, but it should have Smurfs.
+    expect(formatted.contains('Smurfs'), isTrue);
+  });
 }