Add a failing test for handling broken symlinks.

utils/tests/pub/install/broken_symlink_test.dart

Index: utils/tests/pub/install/broken_symlink_test.dart
diff --git a/utils/tests/pub/install/relative_symlink_test.dart b/utils/tests/pub/install/broken_symlink_test.dart
similarity index 58%
copy from utils/tests/pub/install/relative_symlink_test.dart
copy to utils/tests/pub/install/broken_symlink_test.dart
index 166a7caa0636c833037fb031b2dc71da486b4f34..07a5530f556242269b8065c98cbe31b57ddc920f 100644
--- a/utils/tests/pub/install/relative_symlink_test.dart
+++ b/utils/tests/pub/install/broken_symlink_test.dart
@@ -6,50 +6,51 @@ library pub_tests;
 
 import 'dart:io';
 
+import '../../../../pkg/pathos/lib/path.dart' as path;
 import '../../../../pkg/unittest/lib/unittest.dart';
+
 import '../test_pub.dart';
 
 main() {
-  // Pub uses NTFS junction points to create links in the packages directory.
-  // These (unlike the symlinks that are supported in Vista and later) do not
-  // support relative paths. So this test, by design, will not pass on Windows.
-  // So just skip it.
-  if (Platform.operatingSystem == "windows") return;
-
   initConfig();
-  integration('uses a relative symlink for the self link', () {
+  integration('replaces a broken "packages" symlink', () {
     dir(appPath, [
       appPubspec([]),
-      libDir('foo')

[Andrei Mouravski, 2013/03/06 01:25:46]

Could you make all "s into 's?

[Bob Nystrom, 2013/03/06 20:55:55]

Pub doesn't really have a well-defined guideline for when to prefer one string
style or another. We need to figure one out, but we haven't. Right now, it's
just a mixed bag.

+      libDir('foo'),
+      dir("bin")
     ]).scheduleCreate();
 
+    // Create a broken "packages" symlink in "bin".

[nweiz, 2013/03/06 20:13:52]

'"bin"' -> 'the package root'

+    scheduleSymlink("nonexistent", path.join(appPath, "packages"));
+
     schedulePub(args: ['install'],
         output: new RegExp(r"Dependencies installed!$"));
 
-    scheduleRename(appPath, "moved");
-
-    dir("moved", [
-      dir("packages", [
-        dir("myapp", [
-          file('foo.dart', 'main() => "foo";')
+    dir(appPath, [
+      dir("bin", [
+        dir("packages", [
+          dir("myapp", [
+            file('foo.dart', 'main() => "foo";')
+          ])
         ])
       ])
     ]).scheduleValidate();
   });
 
-  integration('uses a relative symlink for secondary packages directory', () {
+  integration('replaces a broken secondary "packages" symlink', () {
     dir(appPath, [
       appPubspec([]),
       libDir('foo'),
       dir("bin")
     ]).scheduleCreate();
 
+    // Create a broken "packages" symlink in "bin".
+    scheduleSymlink("nonexistent", path.join(appPath, "bin", "packages"));
+
     schedulePub(args: ['install'],
         output: new RegExp(r"Dependencies installed!$"));
 
-    scheduleRename(appPath, "moved");
-
-    dir("moved", [
+    dir(appPath, [
       dir("bin", [
         dir("packages", [
           dir("myapp", [