Added the continueParsing option to ArgParser.

pkg/args/test/parse_all_test.dart

Index: pkg/args/test/parse_all_test.dart
diff --git a/pkg/args/test/parse_all_test.dart b/pkg/args/test/parse_all_test.dart
index a921046465786147256074fb58c14bd3cc17ec4e..2df05189630c707daf75931c295704832706038d 100644
--- a/pkg/args/test/parse_all_test.dart
+++ b/pkg/args/test/parse_all_test.dart
@@ -8,7 +8,8 @@ import 'package:unittest/unittest.dart';
 import 'package:args/args.dart';
 
 main() {
-  group('ArgParser.parse() starting with a non-option', () {
+  group('ArgParser.parse(allowTrailingOptions: true) '
+        'starting with a non-option', () {
     test('followed by flag', () {
       var parser = new ArgParser()..addFlag('flag');
       var args = ['A', '--flag'];
@@ -16,6 +17,9 @@ main() {
       var results = parser.parse(args);
       expect(results['flag'], isFalse);
       expect(results.rest, orderedEquals(args));
+      var resultsAll = parser.parse(args, allowTrailingOptions: true);
+      expect(resultsAll['flag'], isTrue);
+      expect(resultsAll.rest, equals(['A']));
     });
 
     test('followed by option', () {
@@ -25,6 +29,8 @@ main() {
       var results = parser.parse(args);
       expect(results['opt'], isNull);
       expect(results.rest, orderedEquals(args));
+
+      expectThrows(parser, args);
     });
 
     test('followed by option and value', () {
@@ -34,6 +40,10 @@ main() {
       var results = parser.parse(args);
       expect(results['opt'], isNull);
       expect(results.rest, orderedEquals(args));
+
+      var resultsAll = parser.parse(args, allowTrailingOptions: true);
+      expect(resultsAll['opt'], equals('V'));
+      expect(resultsAll.rest, equals(['A']));
     });
 
     test('followed by unknown flag', () {
@@ -41,6 +51,8 @@ main() {
       var args = ['A', '--xflag'];
       var results = parser.parse(args);
       expect(results.rest, orderedEquals(args));
+
+      expectThrows(parser, args);
     });
 
     test('followed by unknown option and value', () {
@@ -48,6 +60,8 @@ main() {
       var args = ['A', '--xopt', 'V'];
       var results = parser.parse(args);
       expect(results.rest, orderedEquals(args));
+
+      expectThrows(parser, args);
     });
 
     test('followed by command', () {
@@ -57,6 +71,12 @@ main() {
       var results = parser.parse(args);
       expect(results.command, isNull);
       expect(results.rest, orderedEquals(args));
+
+      expectThrows(parser, args);
     });
   });
 }
+expectThrows(ArgParser parser, List<String> args) =>
+  expect(() => parser.parse(args, allowTrailingOptions: true),
+      throwsFormatException,
+      reason: "with allowTrailingOptions: true");