Add new SpanScanner.eager().

test/span_scanner_test.dart

 // Copyright (c) 2014, 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 string_scanner.span_scanner_test;
 
 import 'package:string_scanner/string_scanner.dart';
 import 'package:test/test.dart';
 
 void main() {
-  var scanner;
-  setUp(() {
-    scanner = new SpanScanner('foo\nbar\nbaz', sourceUrl: 'source');
+  testForImplementation("lazy", () {
+    return new SpanScanner('foo\nbar\nbaz', sourceUrl: 'source');
   });
 
-  test("tracks the span for the last match", () {
-    scanner.scan('fo');
-    scanner.scan('o\nba');
-
-    var span = scanner.lastSpan;
-    expect(span.start.offset, equals(2));
-    expect(span.start.line, equals(0));
-    expect(span.start.column, equals(2));
-    expect(span.start.sourceUrl, equals(Uri.parse('source')));
-
-    expect(span.end.offset, equals(6));
-    expect(span.end.line, equals(1));
-    expect(span.end.column, equals(2));
-    expect(span.start.sourceUrl, equals(Uri.parse('source')));
-
-    expect(span.text, equals('o\nba'));
-  });
-
-  test(".spanFrom() returns a span from a previous state", () {
-    scanner.scan('fo');
-    var state = scanner.state;
-    scanner.scan('o\nba');
-    scanner.scan('r\nba');
-
-    var span = scanner.spanFrom(state);
-    expect(span.text, equals('o\nbar\nba'));
-  });
-
-  test(".emptySpan returns an empty span at the current location", () {
-    scanner.scan('foo\nba');
-
-    var span = scanner.emptySpan;
-    expect(span.start.offset, equals(6));
-    expect(span.start.line, equals(1));
-    expect(span.start.column, equals(2));
-    expect(span.start.sourceUrl, equals(Uri.parse('source')));
-
-    expect(span.end.offset, equals(6));
-    expect(span.end.line, equals(1));
-    expect(span.end.column, equals(2));
-    expect(span.start.sourceUrl, equals(Uri.parse('source')));
-
-    expect(span.text, equals(''));
+  testForImplementation("eager", () {
+    return new SpanScanner.eager('foo\nbar\nbaz', sourceUrl: 'source');
   });
 }
+
+void testForImplementation(String name, SpanScanner create()) {
+  group("for a $name scanner", () {
+    var scanner;
+    setUp(() => scanner = create());
+
+    test("tracks the span for the last match", () {
+      scanner.scan('fo');
+      scanner.scan('o\nba');
+
+      var span = scanner.lastSpan;
+      expect(span.start.offset, equals(2));
+      expect(span.start.line, equals(0));
+      expect(span.start.column, equals(2));
+      expect(span.start.sourceUrl, equals(Uri.parse('source')));
+
+      expect(span.end.offset, equals(6));
+      expect(span.end.line, equals(1));
+      expect(span.end.column, equals(2));
+      expect(span.start.sourceUrl, equals(Uri.parse('source')));
+
+      expect(span.text, equals('o\nba'));
+    });
+
+    test(".spanFrom() returns a span from a previous state", () {
+      scanner.scan('fo');
+      var state = scanner.state;
+      scanner.scan('o\nba');
+      scanner.scan('r\nba');
+
+      var span = scanner.spanFrom(state);
+      expect(span.text, equals('o\nbar\nba'));
+    });
+
+    test(".emptySpan returns an empty span at the current location", () {
+      scanner.scan('foo\nba');
+
+      var span = scanner.emptySpan;
+      expect(span.start.offset, equals(6));
+      expect(span.start.line, equals(1));
+      expect(span.start.column, equals(2));
+      expect(span.start.sourceUrl, equals(Uri.parse('source')));
+
+      expect(span.end.offset, equals(6));
+      expect(span.end.line, equals(1));
+      expect(span.end.column, equals(2));
+      expect(span.start.sourceUrl, equals(Uri.parse('source')));
+
+      expect(span.text, equals(''));
+    });
+  });
+}