Strings recipes for the Dart Cookbook

recipes/test/core/strings/converting_between_string_characters_test.dart

Index: recipes/test/core/strings/converting_between_string_characters_test.dart
diff --git a/recipes/test/core/strings/converting_between_string_characters_test.dart b/recipes/test/core/strings/converting_between_string_characters_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..583dfa15bd453ebd3ad80444cf831575e35fa2c3
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+++ b/recipes/test/core/strings/converting_between_string_characters_test.dart
@@ -0,0 +1,80 @@
+library converting_between_string_characters_test;
+
+import 'package:unittest/unittest.dart';
+
+
+void main() {
+  group('converting between string characters and numerical codes', () {
+    var smileyFace = '\u263A';
+    var clef = '\u{1F3BC}';
+    
+    group('using runes', () {
+      test('', () {
+        expect('Dart'.runes.toList(), equals([68, 97, 114, 116]));
+        
+        expect(smileyFace.runes.toList(), equals([9786]));
+        expect(smileyFace.runes.first.toRadixString(16), equals('263a'));
+
+        expect(clef.runes.toList(), equals([127932]));
+        expect(clef.runes.first.toRadixString(16), equals('1f3bc'));
+      });
+    });
+    
+    group('using codeUnits', () {
+      test('', () {
+        expect('Dart'.codeUnits.toList(), equals([68, 97, 114, 116]));
+        
+        expect(smileyFace.codeUnits.toList(), equals([9786]));
+        expect(smileyFace.codeUnits.first.toRadixString(16), equals('263a'));
+
+        expect(clef.codeUnits.toList(), equals([55356, 57276]));
+        expect(clef.codeUnits.map((codeUnit) => codeUnit.toRadixString(16))
+          .toList(), equals(['d83c', 'dfbc']));
+      });
+    });
+    
+    group('using codeUnitAt', () {
+      test('', () {
+        expect('Dart'.codeUnitAt(0), equals(68));
+        
+        expect(smileyFace.codeUnitAt(0), equals(9786)); // 9786
+        expect(smileyFace.codeUnitAt(0).toRadixString(16), equals('263a'));
+        
+        expect(clef.codeUnitAt(0), equals(55356));
+        expect(clef.codeUnitAt(0).toRadixString(16), equals('d83c'));
+        expect(clef.codeUnitAt(1), equals(57276));
+       expect(clef.codeUnitAt(1).toRadixString(16), equals('dfbc'));
+      });
+    });
+ 
+    group('using fromCharCodes', () {
+      var heart = '\u2661';
+      
+      test('', () {
+        expect(new String.fromCharCodes([68, 97, 114, 116]), equals('Dart'));
+        expect(new String.fromCharCodes([73, 32, 9825, 32, 76, 117, 99, 121]),
+            equals("I $heart Lucy"));
+      });
+      
+      test('', () {
+        expect(new String.fromCharCodes([9786]), equals(smileyFace));
+      });
+      
+      test('with surrogate pair codeUnits', () {
+        expect(new String.fromCharCodes([55356, 57276]), equals(clef));
+      });
+      
+      test('with rune', () {
+        expect(new String.fromCharCode(127932), equals(clef));
+      });
+    });
+    
+    group('using fromCharCode', () {      
+      test('', () {
+        expect(new String.fromCharCode(68), equals('D'));
+        expect(new String.fromCharCode(9786), equals(smileyFace));
+        expect(new String.fromCharCode(127932), equals(clef));
+      });
+    });
+  });
+}