Renamed refresh to setup and removed alias function & added unittest

Renamed to simplify and avoid issue with nose tests trying to use
`setup` as a setup for testing. Unittest implements basic test for
refreshing with a bad git path versus a good git path.

Author: kenodegard

git/__init__.py

@@ -58,19 +58,16 @@ def _init_externals():
 __all__ = [name for name, obj in locals().items()
            if not (name.startswith('_') or inspect.ismodule(obj))]
 
+
 #{ Initialize git executable path
-def setup(path=None):
+def refresh(path=None):
     """Convenience method for setting the git executable path."""
     if not Git.refresh(path=path):
         return
     if not FetchInfo.refresh():
         return
-
-def refresh(path=None):
-    """Convenience method for refreshing the git executable path."""
-    setup(path=path)
 #} END initialize git executable path
 
 #################
-setup()
+refresh()
 #################

git/test/test_git.py

@@ -10,6 +10,7 @@
 
 from git import (
     Git,
+    refresh,
     GitCommandError,
     GitCommandNotFound,
     Repo,
@@ -156,6 +157,14 @@ def test_cmd_override(self):
             type(self.git).GIT_PYTHON_GIT_EXECUTABLE = prev_cmd
         # END undo adjustment
 
+    def test_refresh(self):
+        # test a bad git path refresh
+        self.assertRaises(GitCommandNotFound, refresh, "yada")
+
+        # test a good path refresh
+        path = os.popen("which git").read().strip()
+        refresh(path)
+
     def test_options_are_passed_to_git(self):
         # This work because any command after git --version is ignored
         git_version = self.git(version=True).NoOp()