Strings recipes for the Dart Cookbook

recipes/test/core/strings/subscripting_strings_test.dart

Index: recipes/test/core/strings/subscripting_strings_test.dart
diff --git a/recipes/test/core/strings/subscripting_strings_test.dart b/recipes/test/core/strings/subscripting_strings_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..9a548027519c588578357a31d212c70067a3e090
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+++ b/recipes/test/core/strings/subscripting_strings_test.dart
@@ -0,0 +1,33 @@
+library subscripting_strings_test;
+
+import 'package:unittest/unittest.dart';
+
+void main() {
+  group('getting the character at a specific index', () {
+    group('with non-BMP symbol', () {
+      var hearts = '\u2661';
+      
+      test('with BMP symbols', () {
+        expect('Dart'[0], equals('D'));
+        expect(hearts[0], equals('\u2661'));
+      });      
+    });
+
+    group("with non-BMP symbol", () {
+      var coffee = '\u{1F375}';
+      var doughnuts = '\u{1F369}';
+      var healthFood = '$coffee and $doughnuts';
+      test('with non-BMP symbol', () {
+
+        // expect(healthFood[0], equals('?'));
+        expect(healthFood.slice(0, 2), equals(coffee));
+      }); 
+      
+      test('', () {
+        expect(healthFood.runes.first, equals(127861));
+        expect(new String.fromCharCode(127861), equals(coffee));
+        expect(healthFood.codeUnits.first, equals(55356));
+      }); 
+    });
+  });
+}