Fix mobolic#161.

Fix regression described in mobolic#161 by adding a default API version to all
calls.

Note that while the default version is 1.0, Facebook will automatically
coerce API calls to later versions for newer applications that are
unable to access this version.

facebook/__init__.py

@@ -82,11 +82,15 @@ class GraphAPI(object):
     for the active user from the cookie saved by the SDK.
 
     """
+
     def __init__(self, access_token=None, timeout=None, version=None):
+        # The default version is only used if the version kwarg does not exist.
+        default_version = "1.0"
+        valid_API_versions = ["1.0", "2.0", "2.1"]
+
         self.access_token = access_token
         self.timeout = timeout
 
-        valid_API_versions = ["1.0", "2.0", "2.1"]
         if version:
             version_regex = re.compile("^\d\.\d$")
             match = version_regex.search(str(version))
@@ -100,7 +104,7 @@ def __init__(self, access_token=None, timeout=None, version=None):
                 raise GraphAPIError("Version number should be in the"
                                     " following format: #.# (e.g. 1.0).")
         else:
-            self.version = ""
+            self.version = "v" + default_version
 
     def get_object(self, id, **args):
         """Fetchs the given object from the graph."""

test/test_facebook.py

@@ -44,6 +44,12 @@ def test_get_app_access_token(self):
 
 class TestAPIVersion(FacebookTestCase):
     """Test if using the correct version of Graph API."""
+    def test_no_version(self):
+        graph = facebook.GraphAPI()
+        self.assertNotEqual(graph.version, None, "Version should not be None.")
+        self.assertNotEqual(
+            graph.version, "", "Version should not be an empty string.")
+
     def test_version_1_0(self):
         graph = facebook.GraphAPI(version=1.0)
         self.assertEqual(graph.get_version(), 1.0)