Add the ability to get the current directory

tests/standalone/src/io/DirectoryTest.dart

Index: tests/standalone/src/io/DirectoryTest.dart
diff --git a/tests/standalone/src/io/DirectoryTest.dart b/tests/standalone/src/io/DirectoryTest.dart
index ad8c7c92529eb7e3d32936e0649fad102ae705b9..83f22afdb64bbf0b486c9f28eef0ede6d9203f9c 100644
--- a/tests/standalone/src/io/DirectoryTest.dart
+++ b/tests/standalone/src/io/DirectoryTest.dart
@@ -353,6 +353,13 @@ class DirectoryTest {
     });
   }
 
+  static void testCurrent() {
+    Directory current = new Directory.current();
+    if (new Platform().operatingSystem() != "windows") {
+      Expect.equals("/", current.path.substring(0, 1));

[Bill Hesse, 2012/03/08 11:26:34]

Why can't we test that Directory.current() is the same as
Directory(".").fullPath?

I always used Directory('.') for the current directory - Why isn't that
sufficient?  Or just Directory('.').fullPath()?

+    }
+  }
+
   static void testMain() {
     testListing();
     testListNonExistent();
@@ -365,6 +372,7 @@ class DirectoryTest {
     testExistsCreateDeleteSync();
     testCreateTemp();
     testCreateDeleteTemp();
+    testCurrent();
   }
 }