Add unit tests for the tempest.common.utils.file_utils

This commit adds a positive and negative unit tests for the single
method from file_utils in tempest.common.utils.

Partially implements bp unit-tests

Change-Id: Ic19428a10785afd8849442f4d1f8f8e0a87f549b
diff --git a/tempest/tests/common/utils/test_file_utils.py b/tempest/tests/common/utils/test_file_utils.py
new file mode 100644
index 0000000..99ae033
--- /dev/null
+++ b/tempest/tests/common/utils/test_file_utils.py
@@ -0,0 +1,32 @@
+# Copyright 2014 IBM Corp.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import mock
+from mock import patch
+
+from tempest.common.utils import file_utils
+from tempest.tests import base
+
+
+class TestFileUtils(base.TestCase):
+
+    def test_have_effective_read_path(self):
+        with patch('__builtin__.open', mock.mock_open(), create=True):
+            result = file_utils.have_effective_read_access('fake_path')
+        self.assertTrue(result)
+
+    def test_not_effective_read_path(self):
+        result = file_utils.have_effective_read_access('fake_path')
+        self.assertFalse(result)