Add StringScanner.scanChar() and .expectChar().

test/string_scanner_test.dart

Index: test/string_scanner_test.dart
diff --git a/test/string_scanner_test.dart b/test/string_scanner_test.dart
index 10e622a82a3cc2268eaf913e7aec260799e10f8f..0b4d4824f0bf2bf64cb85f4799d4cdceb004fc07 100644
--- a/test/string_scanner_test.dart
+++ b/test/string_scanner_test.dart
@@ -2,6 +2,7 @@
 // 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:charcode/charcode.dart';
 import 'package:string_scanner/string_scanner.dart';
 import 'package:test/test.dart';
 
@@ -41,6 +42,18 @@ void main() {
       expect(scanner.position, equals(0));
     });
 
+    test("scanChar returns false and doesn't change the state", () {
+      expect(scanner.scanChar($f), isFalse);
+      expect(scanner.lastMatch, isNull);
+      expect(scanner.position, equals(0));
+    });
+
+    test("expectChar fails and doesn't change the state", () {
+      expect(() => scanner.expectChar($f), throwsFormatException);
+      expect(scanner.lastMatch, isNull);
+      expect(scanner.position, equals(0));
+    });
+
     test("scan returns false and doesn't change the state", () {
       expect(scanner.scan(new RegExp('.')), isFalse);
       expect(scanner.lastMatch, isNull);
@@ -117,6 +130,30 @@ void main() {
       expect(scanner.position, equals(0));
     });
 
+    test("a matching scanChar returns true moves forward", () {
+      expect(scanner.scanChar($f), isTrue);
+      expect(scanner.lastMatch, isNull);
+      expect(scanner.position, equals(1));
+    });
+
+    test("a non-matching scanChar returns false and does nothing", () {
+      expect(scanner.scanChar($x), isFalse);
+      expect(scanner.lastMatch, isNull);
+      expect(scanner.position, equals(0));
+    });
+
+    test("a matching expectChar moves forward", () {
+      scanner.expectChar($f);
+      expect(scanner.lastMatch, isNull);
+      expect(scanner.position, equals(1));
+    });
+
+    test("a non-matching expectChar fails", () {
+      expect(() => scanner.expectChar($x), throwsFormatException);
+      expect(scanner.lastMatch, isNull);
+      expect(scanner.position, equals(0));
+    });
+
     test("a matching scan returns true and changes the state", () {
       expect(scanner.scan(new RegExp('f(..)')), isTrue);
       expect(scanner.lastMatch[1], equals('oo'));
@@ -256,6 +293,18 @@ void main() {
       expect(scanner.position, equals(7));
     });
 
+    test("scanChar returns false and doesn't change the state", () {
+      expect(scanner.scanChar($f), isFalse);
+      expect(scanner.lastMatch, isNotNull);
+      expect(scanner.position, equals(7));
+    });
+
+    test("expectChar fails and doesn't change the state", () {
+      expect(() => scanner.expectChar($f), throwsFormatException);
+      expect(scanner.lastMatch, isNotNull);
+      expect(scanner.position, equals(7));
+    });
+
     test("scan returns false and sets lastMatch to null", () {
       expect(scanner.scan(new RegExp('.')), isFalse);
       expect(scanner.lastMatch, isNull);