Split the args tests into a couple of smaller suites.

pkg/args/test/usage_test.dart

+// Copyright (c) 2012, 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 args_test;
+
+import 'package:unittest/unittest.dart';
+import 'package:args/args.dart';
+
+main() {
+  group('ArgParser.getUsage()', () {
+    test('negatable flags show "no-" in title', () {
+      var parser = new ArgParser();
+      parser.addFlag('mode', help: 'The mode');
+
+      validateUsage(parser,
+          '''
+          --[no-]mode    The mode
+          ''');
+    });
+
+    test('non-negatable flags don\'t show "no-" in title', () {
+      var parser = new ArgParser();
+      parser.addFlag('mode', negatable: false, help: 'The mode');
+
+      validateUsage(parser,
+          '''
+          --mode    The mode
+          ''');
+    });
+
+    test('if there are no abbreviations, there is no column for them', () {
+      var parser = new ArgParser();
+      parser.addFlag('mode', help: 'The mode');
+
+      validateUsage(parser,
+          '''
+          --[no-]mode    The mode
+          ''');
+    });
+
+    test('options are lined up past abbreviations', () {
+      var parser = new ArgParser();
+      parser.addFlag('mode', abbr: 'm', help: 'The mode');
+      parser.addOption('long', help: 'Lacks an abbreviation');
+
+      validateUsage(parser,
+          '''
+          -m, --[no-]mode    The mode
+              --long         Lacks an abbreviation
+          ''');
+    });
+
+    test('help text is lined up past the longest option', () {
+      var parser = new ArgParser();
+      parser.addFlag('mode', abbr: 'm', help: 'Lined up with below');
+      parser.addOption('a-really-long-name', help: 'Its help text');
+
+      validateUsage(parser,
+          '''
+          -m, --[no-]mode             Lined up with below
+              --a-really-long-name    Its help text
+          ''');
+    });
+
+    test('leading empty lines are ignored in help text', () {
+      var parser = new ArgParser();
+      parser.addFlag('mode', help: '\n\n\n\nAfter newlines');
+
+      validateUsage(parser,
+          '''
+          --[no-]mode    After newlines
+          ''');
+    });
+
+    test('trailing empty lines are ignored in help text', () {
+      var parser = new ArgParser();
+      parser.addFlag('mode', help: 'Before newlines\n\n\n\n');
+
+      validateUsage(parser,
+          '''
+          --[no-]mode    Before newlines
+          ''');
+    });
+
+    test('options are documented in the order they were added', () {
+      var parser = new ArgParser();
+      parser.addFlag('zebra', help: 'First');
+      parser.addFlag('monkey', help: 'Second');
+      parser.addFlag('wombat', help: 'Third');
+
+      validateUsage(parser,
+          '''
+          --[no-]zebra     First
+          --[no-]monkey    Second
+          --[no-]wombat    Third
+          ''');
+    });
+
+    test('the default value for a flag is shown if on', () {
+      var parser = new ArgParser();
+      parser.addFlag('affirm', help: 'Should be on', defaultsTo: true);
+      parser.addFlag('negate', help: 'Should be off', defaultsTo: false);
+
+      validateUsage(parser,
+          '''
+          --[no-]affirm    Should be on
+                           (defaults to on)
+
+          --[no-]negate    Should be off
+          ''');
+    });
+
+    test('the default value for an option with no allowed list is shown', () {
+      var parser = new ArgParser();
+      parser.addOption('any', help: 'Can be anything', defaultsTo: 'whatevs');
+
+      validateUsage(parser,
+          '''
+          --any    Can be anything
+                   (defaults to "whatevs")
+          ''');
+    });
+
+    test('the allowed list is shown', () {
+      var parser = new ArgParser();
+      parser.addOption('suit', help: 'Like in cards',
+          allowed: ['spades', 'clubs', 'hearts', 'diamonds']);
+
+      validateUsage(parser,
+          '''
+          --suit    Like in cards
+                    [spades, clubs, hearts, diamonds]
+          ''');
+    });
+
+    test('the default is highlighted in the allowed list', () {
+      var parser = new ArgParser();
+      parser.addOption('suit', help: 'Like in cards', defaultsTo: 'clubs',
+          allowed: ['spades', 'clubs', 'hearts', 'diamonds']);
+
+      validateUsage(parser,
+          '''
+          --suit    Like in cards
+                    [spades, clubs (default), hearts, diamonds]
+          ''');
+    });
+
+    test('the allowed help is shown', () {
+      var parser = new ArgParser();
+      parser.addOption('suit', help: 'Like in cards', defaultsTo: 'clubs',
+          allowed: ['spades', 'clubs', 'diamonds', 'hearts'],
+          allowedHelp: {
+            'spades': 'Swords of a soldier',
+            'clubs': 'Weapons of war',
+            'diamonds': 'Money for this art',
+            'hearts': 'The shape of my heart'
+          });
+
+      validateUsage(parser,
+          '''
+          --suit              Like in cards
+
+                [clubs]       Weapons of war
+                [diamonds]    Money for this art
+                [hearts]      The shape of my heart
+                [spades]      Swords of a soldier
+          ''');
+    });
+  });
+}
+
+throwsIllegalArg(function) {
+  expect(function, throwsArgumentError);
+}
+
+validateUsage(ArgParser parser, String expected) {
+  expected = unindentString(expected);
+  expect(parser.getUsage(), equals(expected));
+}
+
+// TODO(rnystrom): Replace one in test_utils.
+String unindentString(String text) {
+  var lines = text.split('\n');
+
+  // Count the indentation of the last line.
+  var whitespace = new RegExp('^ *');
+  var indent = whitespace.firstMatch(lines[lines.length - 1])[0].length;
+
+  // Drop the last line. It only exists for specifying indentation.
+  lines.removeLast();
+
+  // Strip indentation from the remaining lines.
+  for (var i = 0; i < lines.length; i++) {
+    var line = lines[i];
+    if (line.length <= indent) {
+      // It's short, so it must be nothing but whitespace.
+      if (line.trim() != '') {
+        throw new ArgumentError(
+            'Line "$line" does not have enough indentation.');
+      }
+
+      lines[i] = '';
+    } else {
+      if (line.substring(0, indent).trim() != '') {
+        throw new ArgumentError(
+            'Line "$line" does not have enough indentation.');
+      }
+
+      lines[i] = line.substring(indent);
+    }
+  }
+
+  return Strings.join(lines, '\n');
+}