Win, #519: FIX repo TCs.

+ FIX TestRepo.test_submodule_update():
  + submod: del `.git` file prior overwrite; Windows denied otherwise!
+ FIX TestRepo.test_untracked_files():
  + In the `git add <file>` case, it failed with unicode args on PY2.
Had to
encode them with `locale.getpreferredencoding()` AND use SHELL.
+ cmd: add `shell` into `execute()` kwds, for overriding USE_SHELL per
command.
+ repo: replace blocky `communicate()` in `_clone()` with thread-pumps.
+ test_repo.py: unittestize (almost  all) assertions.
+ Replace open --> with open for index (base and TC).
+ test_index.py: Enabled a dormant assertion. 

1 files changed, 12 insertions, 9 deletions

diff --git a/git/objects/submodule/base.py b/git/objects/submodule/base.py
index fb5f774d..3196ef8f 100644
--- a/git/objects/submodule/base.py
+++ b/git/objects/submodule/base.py
@@ -29,7 +29,8 @@ from git.exc import (
 )
 from git.compat import (
     string_types,
-    defenc
+    defenc,
+    is_win,
 )
 
 import stat
@@ -289,14 +290,16 @@ class Submodule(util.IndexObject, Iterable, Traversable):
         """
         git_file = os.path.join(working_tree_dir, '.git')
         rela_path = os.path.relpath(module_abspath, start=working_tree_dir)
-        fp = open(git_file, 'wb')
-        fp.write(("gitdir: %s" % rela_path).encode(defenc))
-        fp.close()
-
-        writer = GitConfigParser(os.path.join(module_abspath, 'config'), read_only=False, merge_includes=False)
-        writer.set_value('core', 'worktree',
-                         to_native_path_linux(os.path.relpath(working_tree_dir, start=module_abspath)))
-        writer.release()
+        if is_win:
+            if os.path.isfile(git_file):
+                os.remove(git_file)
+        with open(git_file, 'wb') as fp:
+            fp.write(("gitdir: %s" % rela_path).encode(defenc))
+
+        with GitConfigParser(os.path.join(module_abspath, 'config'),
+                             read_only=False, merge_includes=False) as writer:
+            writer.set_value('core', 'worktree',
+                             to_native_path_linux(os.path.relpath(working_tree_dir, start=module_abspath)))
 
     #{ Edit Interface