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.
+//
+// Test the Path class in dart:io.
+
+#import("dart:io");
+
+void main() {
+  testBaseFunctions();
+  testCanonicalize();
+}
+
+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');
+  // This corner case leaves a trailing slash for the root.
+  testGetters(new Path('/'),
+    ['/', '', '', ''],
+    'absolute directory canonical trailing');
+  testGetters(new Path('.'),
+    ['', '.', '', ''],
+    'canonical');
+  testGetters(new Path('/ab,;- .c.d'),
+    ['/', 'ab,;- .c.d', 'ab,;- .c', 'd'],
+    'absolute directory canonical');
+
+  // Canonical and 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 trailing');
+
+  // Test the special path cleaning operations on the Windows platform.
+  if (Platform.operatingSystem == 'windows') {
+    testGetters(new Path.fromNative(@"c:\foo\bar\fisk.hest"),
+                ['/c:/foo/bar', 'fisk.hest', 'fisk', 'hest'],
+                'absolute canonical');
+    testGetters(new Path.fromNative("\\foo\\bar\\"),
+                ['/foo/bar', '', '', ''],
+                'absolute directory canonical trailing');
+    testGetters(new Path.fromNative("\\foo\\bar\\hest"),
+                ['/foo/bar', 'hest', 'hest', ''],
+                'absolute canonical');
+    testGetters(new Path.fromNative(@"foo/bar\hest/.fisk"),
+                ['foo/bar/hest', '.fisk', '', 'fisk'],
+                'canonical');
+    testGetters(new Path.fromNative(@"foo//bar\\hest/\/.fisk"),
+                ['foo//bar//hest//', '.fisk', '', 'fisk'],
+                '');
+  } else {
+    // Make sure that backslashes are uninterpreted on other platforms.
+    testGetters(new Path.fromNative(@"/foo\bar/bif/fisk.hest"),
+                [@'/foo\bar/bif', 'fisk.hest', 'fisk', 'hest'],
+                'absolute canonical');
+    testGetters(new Path.fromNative(@"//foo\bar///bif////fisk.hest"),
+                [@'//foo\bar///bif', 'fisk.hest', 'fisk', 'hest'],
+                'absolute');
+    testGetters(new Path.fromNative(@"/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.directoryPath.toString());
+  Expect.equals(components[FILENAME], path.filename);
+  Expect.equals(components[BASENAME], path.filenameWithoutExtension);
+  Expect.equals(components[EXTENSION], path.extension);
+
+  Expect.equals(path.isCanonical, properties.contains('canonical'));
+  Expect.equals(path.isAbsolute, properties.contains('absolute'));
+  Expect.equals(path.hasTrailingSeparator, properties.contains('trailing'));
+}
+
+void testCanonicalize() {
+  Function t = (input, canonicalized) {
+    Expect.equals(canonicalized, new Path(input).canonicalize().toString());
+  };
+
+  t('.', '.');
+  t('./.', '.');
+  t('foo/..', '.');
+  t('../foo', '../foo');
+  t('/../foo', '/foo');
+  t('/foo/..', '/');
+  t('/foo/../', '/');
+  t('/c:/../foo', '/c:/foo');
+  t('/c:/foo/..', '/c:/');
+  t('/c:/foo/../', '/c:/');
+  t('/c:/foo/../..', '/c:/');
+  t('/c:/foo/../../', '/c:/');
+  t('..', '..');
+  t('', '.');
+  t('/', '/');
+  t('../foo/bar/..', '../foo');
+  t('/../foo/bar/..', '/foo');
+  t('foo/bar/../../../joe/../..', '../..');
+  t('a/b/c/../../..d/./.e/f././', 'a/..d/.e/f./');
+  t('/%:/foo/../..', '/%:/');
+  t('c:/foo/../../..', '..');
+  t('c:/foo/../../bad/dad/./..', 'bad');
+}