Skip long repr tests when the cached pyc file's path length would exceed the…

Skip long repr tests when the cached pyc file's path length would exceed the maximum Win32 path length.
This should fix a failure on one of the XP buildbots.

Lib/test/test_reprlib.py

@@ -3,6 +3,7 @@
   Nick Mathewson
 """
 
+import imp
 import sys
 import os
 import shutil
@@ -199,10 +200,11 @@ def write_file(path, text):
         fp.write(text)
 
 class LongReprTest(unittest.TestCase):
+    longname = 'areallylongpackageandmodulenametotestreprtruncation'
+
     def setUp(self):
-        longname = 'areallylongpackageandmodulenametotestreprtruncation'
-        self.pkgname = os.path.join(longname)
-        self.subpkgname = os.path.join(longname, longname)
+        self.pkgname = os.path.join(self.longname)
+        self.subpkgname = os.path.join(self.longname, self.longname)
         # Make the package and subpackage
         shutil.rmtree(self.pkgname, ignore_errors=True)
         os.mkdir(self.pkgname)
@@ -232,7 +234,23 @@ class LongReprTest(unittest.TestCase):
                 os.remove(p)
         del sys.path[0]
 
+    def _check_path_limitations(self, module_name):
+        # base directory
+        source_path_len = len(self.here)
+        # a path separator + `longname` (twice)
+        source_path_len += 2 * (len(self.longname) + 1)
+        # a path separator + `module_name` + ".py"
+        source_path_len += len(module_name) + 1 + len(".py")
+        cached_path_len = source_path_len + len(imp.cache_from_source("x.py")) - len("x.py")
+        if os.name == 'nt' and cached_path_len >= 259:
+            # Under Windows, the max path len is 260 including C's terminating
+            # NUL character.
+            # (see http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247%28v=vs.85%29.aspx#maxpath)
+            self.skipTest("test paths too long (%d characters) for Windows' 260 character limit"
+                          % cached_path_len)
+
     def test_module(self):
+        self._check_path_limitations(self.pkgname)
         eq = self.assertEqual
         create_empty_file(os.path.join(self.subpkgname, self.pkgname + '.py'))
         importlib.invalidate_caches()
@@ -242,6 +260,7 @@ class LongReprTest(unittest.TestCase):
         eq(repr(sys), "<module 'sys' (built-in)>")
 
     def test_type(self):
+        self._check_path_limitations('foo')
         eq = self.assertEqual
         write_file(os.path.join(self.subpkgname, 'foo.py'), '''\
 class foo(object):
@@ -258,6 +277,7 @@ class foo(object):
         pass
 
     def test_class(self):
+        self._check_path_limitations('bar')
         write_file(os.path.join(self.subpkgname, 'bar.py'), '''\
 class bar:
     pass
@@ -268,6 +288,7 @@ class bar:
         self.assertEqual(repr(bar.bar), "<class '%s.bar'>" % bar.__name__)
 
     def test_instance(self):
+        self._check_path_limitations('baz')
         write_file(os.path.join(self.subpkgname, 'baz.py'), '''\
 class baz:
     pass
@@ -279,6 +300,7 @@ class baz:
             "<%s.baz object at 0x" % baz.__name__))
 
     def test_method(self):
+        self._check_path_limitations('qux')
         eq = self.assertEqual
         write_file(os.path.join(self.subpkgname, 'qux.py'), '''\
 class aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa: