Add some logging

MANIFEST

@@ -1,5 +1,7 @@
 # file GENERATED by distutils, do NOT edit
 LICENSE.md
 README.rst
+requirements.txt
 setup.py
+version.txt
 versiontag/__init__.py

tests/test_versiontag.py

@@ -2,22 +2,25 @@
 import tempfile
 import unittest
 import os
+import logging
 
 import versiontag
 
 
 def silent_call(*args):
     with open(os.devnull, 'wb') as devnull:
-        subprocess.check_call(args)
+        subprocess.check_call(args, stdout=devnull, stderr=devnull)
 
 
 class VersionTagTest(unittest.TestCase):
     def setUp(self):
+        logging.disable(logging.CRITICAL)
         self.repo_dir = tempfile.TemporaryDirectory()
         os.chdir(self.repo_dir.name)
 
     def tearDown(self):
         self.repo_dir.cleanup()
+        logging.disable(logging.NOTSET)
 
     def _set_author(self):
         silent_call('git', 'config', 'user.email', '[email protected]')

versiontag/__init__.py

@@ -1,9 +1,11 @@
 import os
 import subprocess
 import re
+import logging
 
 
 __default_version__ = 'r0.0.0'
+logger = logging.getLogger(__name__)
 
 
 def __get_git_tag():
@@ -19,21 +21,25 @@ def __get_cache_file():
     return os.path.join(os.getcwd(), 'version.txt')
 
 
+def __open_cache_file(mode):
+    return open(__get_cache_file(), mode)
+
+
 def cache_git_tag():
     try:
         version = __get_git_tag()
+        with __open_cache_file('w') as vf:
+            vf.write(version)
     except:
         version = __default_version__
-    with open(__get_cache_file(), 'w') as vf:
-        vf.write(version)
     return version
 
 
 def get_version(pypi=False):
     version = __default_version__
 
     try:
-        with open(__get_cache_file(), 'r') as vf:
+        with __open_cache_file('r') as vf:
             version = vf.read().strip()
     except:
         pass
@@ -43,6 +49,9 @@ def get_version(pypi=False):
     except:
         pass
 
+    if version == __default_version__:
+        logger.warning("versiontag could not determine package version using cwd %s. Returning default: %s" % (os.getcwd(), __default_version__))
+
     if pypi:
         # Convert to pypi valid version:
         # 1. Drop the r prefix we use on git tags: r1.0.1-12-geaea7b6 => 1.0.1-12-geaea7b6