Move path-manipulation code from io.dart into path.dart.

utils/tests/pub/path/path_posix_test.dart

Index: utils/tests/pub/path/path_posix_test.dart
diff --git a/utils/tests/pub/path/path_posix_test.dart b/utils/tests/pub/path/path_posix_test.dart
index a34c32d57c2c2802e481b4a0c88cef8b52563a84..c71b670c4377352890735e8793e83288d8b18c26 100644
--- a/utils/tests/pub/path/path_posix_test.dart
+++ b/utils/tests/pub/path/path_posix_test.dart
@@ -33,6 +33,25 @@ main() {
     expect(builder.extension(r'a.b\c'), r'.b\c');
   });
 
+  test('rootOf', () {
+    expect(builder.rootOf(''), null);
+    expect(builder.rootOf('a'), null);
+    expect(builder.rootOf('a/b'), null);

[Bob Nystrom, 2012/12/12 00:01:20]

I think these should return empty strings.

[nweiz, 2012/12/12 00:50:37]

See other reply.

+    expect(builder.rootOf('/a/c'), '/');
+    expect(builder.rootOf('/'), '/');
+  });
+
+  test('dirname', () {
+    expect(builder.dirname(''), '.');
+    expect(builder.dirname('a'), '.');
+    expect(builder.dirname('a/b'), 'a');
+    expect(builder.dirname('a/b/c'), 'a/b');
+    expect(builder.dirname('a/b.c'), 'a');
+    expect(builder.dirname('a/'), 'a');
+    expect(builder.dirname('a/.'), 'a');
+    expect(builder.dirname(r'a\b/c'), r'a\b');

[Bob Nystrom, 2012/12/12 00:01:20]

Can you add tests for:

/ -> /
a/b/ -> a/b/  (subject to discussion, i suppose :) )
a/b\c -> a
a// -> a (?)

Also, matching tests on windows.

[nweiz, 2012/12/12 00:50:37]

Done.
The current semantics have this returning "a/b", although it should return "a".
Done.
Current semantics have this returning "a/", although it should return ".".

+  });
+
   test('basename', () {
     expect(builder.basename(''), '');
     expect(builder.basename('a'), 'a');
@@ -104,10 +123,38 @@ main() {
     });
 
     test('ignores parts before an absolute path', () {
+      expect(builder.join('a', '/', 'b', 'c'), '/b/c');
       expect(builder.join('a', '/b', '/c', 'd'), '/c/d');
       expect(builder.join('a', r'c:\b', 'c', 'd'), r'a/c:\b/c/d');
       expect(builder.join('a', r'\\b', 'c', 'd'), r'a/\\b/c/d');
     });
+
+    test('ignores trailing nulls', () {
+      expect(builder.join('a', null), equals('a'));

[Bob Nystrom, 2012/12/12 00:01:20]

Do we want to allow join() with no arguments? It could return ".".

[Bob Nystrom, 2012/12/12 00:01:20]

Everything else doesn't use explicit equals() here. I don't think it adds any
value and it adds more boilerplate to the tests.

[nweiz, 2012/12/12 00:50:37]

I don't think so. Given that we don't have a way to pass varargs, there's no
real use for it.

[nweiz, 2012/12/12 00:50:37]

Every other test in Dart (not to mention Pub) uses it; I think we should follow
the project style.

[Bob Nystrom, 2012/12/12 01:02:13]

This will get pulled out of pub before too long, so consistency there doesn't
matter much to me. What's so bad about this? It's a well-defined part of the
unittest API?

[nweiz, 2012/12/12 02:45:57]

In everything else we stick with the Dart project style. We even poke fun at
dart2js for not following Dart style. It's certainly the Dart style to use
equals() explicitly, and I feel like we should follow the Dart style even when
we don't like it if we expect others to do the same.

[Bob Nystrom, 2012/12/12 04:52:33]

Sure, if it matters that much to you. In that case, I wonder if it's worth
making little one line convenience functions:

expectJoin(arg, expected) {
  expect(builder.join(arg), equals(expected));
}

I'm just trying to minimize the clutter around the args and expected result.
Either way though, I'm fine with changing it.

+      expect(builder.join('a', 'b', 'c', null, null), equals('a/b/c'));
+    });
+
+    test('disallows intermediate nulls', () {
+      expect(() => builder.join('a', null, 'b'), throwsArgumentError);
+      expect(() => builder.join(null, 'a'), throwsArgumentError);
+    });
+  });
+
+  group('split', () {
+    test('simple cases', () {
+      expect(builder.split('foo'), equals(['foo']));
+      expect(builder.split('foo/bar'), equals(['foo', 'bar']));
+      expect(builder.split('foo/bar/baz'), equals(['foo', 'bar', 'baz']));
+      expect(builder.split('foo/../bar/./baz'),
+          equals(['foo', '..', 'bar', '.', 'baz']));
+      expect(builder.split('foo//bar///baz'), equals(['foo', 'bar', 'baz']));
+      expect(builder.split('foo/\\/baz'), equals(['foo', '\\', 'baz']));

[Bob Nystrom, 2012/12/12 00:01:20]

Also tests for:

. -> .
'' -> []
foo/ -> [foo]
// -> [/] ?

[nweiz, 2012/12/12 00:50:37]

Done.

+    });
+
+    test('includes the root for absolute paths', () {
+      expect(builder.split('/foo/bar/baz'), equals(['/', 'foo', 'bar', 'baz']));
+      expect(builder.split('/'), equals(['/']));
+    });
   });
 
   group('normalize', () {
@@ -238,6 +285,10 @@ main() {
       var r = new path.Builder(style: path.Style.posix, root: '/dir.ext');
       expect(r.relative('/dir.ext/file'), 'file');
     });
+
+    test('with a root parameter', () {
+      expect(builder.relative('/foo/bar/baz', to: '/foo/bar'), equals('baz'));

[Bob Nystrom, 2012/12/12 00:01:20]

This is confusing. Does "to" mean "from" here? Isn't the path from
"/foo/bar/baz" to "/foo/bar" ".."?

[nweiz, 2012/12/12 00:50:37]

Changed "to" to "base".

+    });
   });
 
   group('resolve', () {