Add Path class to dart:io, and add unit tests for it.

tests/standalone/io/path_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.
+//
+// Process test program to test that compilation errors in the process
+// exit handler is reported correctly.
+
+#import("dart:io");
+
+// Only here to make editor happy when Path is not in editor's dart:io.
+// Remove these two lines when committing.

[Søren Gjesse, 2012/05/29 07:18:01]

If you are only unit-testing the path library you can just keep these two
#source lines and remove the #import. This way you can also test stuff in _Path
that is not public.

[Bill Hesse, 2012/05/31 15:55:10]

I need to add a mock Platform in that case, unless I include dart:io, but then
Path conflicts with the Path in dart:io.

+//#source("../../../runtime/bin/path.dart");
+//#source("../../../runtime/bin/path_impl.dart");
+
+void main() {
+  testBaseFunctions();
+}
+
+void testBaseFunctions() {
+  testGetters(new Path("/foo/bar/fisk.hest"),
+              ['/foo/bar', 'fisk.hest', 'fisk', 'hest'],
+              'absolute canonical');
+  testGetters(new Path("/foo/bar/fisk.hest"),
+              ['/foo/bar', 'fisk.hest', 'fisk', 'hest'],
+              'absolute canonical');
+  testGetters(new Path("/foo/bar/fisk.hest"),
+              ['/foo/bar', 'fisk.hest', 'fisk', 'hest'],
+              'absolute canonical');
+  testGetters(new Path(''),
+    ['', '', '', ''],
+    'empty canonical');
+  // This corner case leaves a trailing slash for the root.
+  testGetters(new Path('/'),
+    ['/', '', '', ''],
+    'absolute directory canonical');
+  testGetters(new Path('/'),
+    ['/', '', '', ''],
+    'absolute directory canonical');
+  testGetters(new Path('/ab,;- .c.d'),
+    ['/', 'ab,;- .c.d', 'ab,;- .c', 'd'],
+    'absolute directory canonical');
+
+  // Non-canonical cases
+  testGetters(new Path("a/b/../c/./d/e"),
+    ['a/b/../c/./d', 'e', 'e', ''],
+    '');
+  testGetters(new Path("a./b..//..c/.d/e"),
+    ['a./b../..c/.d', 'e', 'e', ''],
+    'canonical');
+  // .. is allowed at the beginning of a canonical relative path.
+  testGetters(new Path("../../a/b/c/d/"),
+    ['../../a/b/c/d', '', '', ''],
+    'canonical directory');
+
+
+
+  // Test the special path cleaning operations on the Windows platform.
+  if (Platform.operatingSystem == 'windows') {
+    testGetters(new Path(@"c:\foo\bar\fisk.hest"),
+                ['/c:/foo/bar', 'fisk.hest', 'fisk', 'hest'],
+                'absolute canonical');
+    testGetters(new Path(@"\foo\bar\"),
+                ['/foo/bar', '', '', ''],
+                'absolute directory canonical');
+    testGetters(new Path("\\foo\\bar\\hest"),
+                ['/foo/bar', 'hest', 'hest', ''],
+                'absolute canonical');
+    testGetters(new Path(@"foo/bar\hest/.fisk"),
+                ['foo/bar/hest', '.fisk', '', 'fisk'],
+                'canonical');
+  } else {
+    // Make sure that backslashes are uninterpreted on other platforms.
+    testGetters(new Path(@"/foo\bar/bif/fisk.hest"),
+                [@'/foo\bar/bif', 'fisk.hest', 'fisk', 'hest'],
+                'absolute canonical');
+    testGetters(new Path(@"/foo\ bar/bif/gule\ fisk.hest"),
+                [@'/foo\ bar/bif', @'gule\ fisk.hest', @'gule\ fisk', 'hest'],
+                'absolute canonical');
+  }
+}
+
+
+void testGetters(Path path, List components, String properties) {
+  final int DIRNAME = 0;
+  final int FILENAME = 1;
+  final int BASENAME = 2;
+  final int EXTENSION = 3;
+  Expect.equals(components[DIRNAME], path.dirname().toString());
+  Expect.equals(components[FILENAME], path.filename());
+  Expect.equals(components[BASENAME], path.basename());
+  Expect.equals(components[EXTENSION], path.extension());
+
+  Expect.equals(path.isCanonical, properties.contains('canonical'));
+}