Fix a test that was broken on Mac OS X. (#2)

Closes #1
diff --git a/test/package_root_info_test.dart b/test/package_root_info_test.dart
index f05f20c..504b972 100644
--- a/test/package_root_info_test.dart
+++ b/test/package_root_info_test.dart
@@ -141,7 +141,9 @@
 
       var resolver = new SyncPackageResolver.root(p.toUri(packagesLink));
 
-      expect(resolver.packagePath("foo"), equals(p.join(sandbox, "foo")));
+      expect(resolver.packagePath("foo"),
+          equals(new Directory(p.join(sandbox, "foo"))
+              .resolveSymbolicLinksSync()));
       expect(resolver.packagePath("bar"), isNull);
     });