Fix parsing bug when config file is empty.

Method 'parse_file_contents' is expected to return
dict object after parsing the policy file, but
it will return None if file is empty currently.
Fix it.

Change-Id: I2841ccdb0f657fdb583e94d889cdd2685d7068b4

2 files changed, 6 insertions, 1 deletions

diff --git a/oslo_policy/policy.py b/oslo_policy/policy.py
index 6480767..6c9dceb 100644
--- a/oslo_policy/policy.py
+++ b/oslo_policy/policy.py
@@ -350,7 +350,7 @@ def parse_file_contents(data):
             # For backwards-compatibility, convert yaml error to ValueError,
             # which is what JSON loader raised.
             raise ValueError(six.text_type(e))
-    return parsed
+    return parsed or {}
 
 
 class Rules(dict):
diff --git a/oslo_policy/tests/test_policy.py b/oslo_policy/tests/test_policy.py
index c0506df..3853951 100644
--- a/oslo_policy/tests/test_policy.py
+++ b/oslo_policy/tests/test_policy.py
@@ -130,6 +130,11 @@ class RulesTestCase(test_base.BaseTestCase):
                           'default')
 
     @mock.patch.object(_parser, 'parse_rule', lambda x: x)
+    def test_load_empty_data(self):
+        result = policy.Rules.load('', 'default')
+        self.assertEqual(result, {})
+
+    @mock.patch.object(_parser, 'parse_rule', lambda x: x)
     def test_load_yaml(self):
         # Test that simplified YAML can be used with load().
         # Show that YAML allows useful comments.