Fix symlink resolution on Windows w/short filenames

Two issues here:
1. os.path.realpath() doesn't resolve symlinks at all prior to Python
   3.8. Best we can do is skip the test there.
2. It doesn't appear that os.path.realpath() is idempotent on Windows
   when path resolution requires both symlink resolution and 8.3/short
   filename resolution. Calling it twice seems to give the result we
   want.

src/catkin_pkg/workspaces.py

@@ -92,8 +92,8 @@ def order_paths(paths_to_order, prefix_paths):
 
 
 def _is_equal_or_in_parents(dir_, path):
-    dir_ = os.path.normcase(os.path.realpath(dir_))
-    path = os.path.normcase(os.path.realpath(path))
+    dir_ = os.path.normcase(os.path.realpath(os.path.realpath(dir_)))
+    path = os.path.normcase(os.path.realpath(os.path.realpath(path)))
     return path == dir_ or path.startswith(dir_ + os.sep)
 
 

test/test_workspaces.py

@@ -2,6 +2,7 @@
 
 import os
 import shutil
+import sys
 import tempfile
 import unittest
 
@@ -43,6 +44,9 @@ def test_order_paths(self):
         self.assertEqual(['foo' + os.sep + 'bim', 'bar'], order_paths(['bar', 'foo' + os.sep + 'bim'], ['foo']))
 
     def test_order_paths_with_symlink(self):
+        if os.name == 'nt' and sys.version_info < (3, 8):
+            self.skipTest('symlinks are not resolved on Windows prior to Python 3.8')
+
         root_dir = tempfile.mkdtemp()
         try:
             foo = os.path.join(root_dir, 'foo')