Add utils's check_string_length test case

1. What is the problem
Tricircle does not have utils module's test case

2. What is the solution to the problem
Implement related test case

3. What the features need to be implemented to the Tricircle
No new features

Change-Id: I42e54cfe310349578ae0605789249acbc349f5e4

tricircle/tests/unit/common/test_utils.py

@@ -0,0 +1,36 @@
+
+# Copyright 2010 United States Government as represented by the
+# Administrator of the National Aeronautics and Space Administration.
+# 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 unittest
+
+from tricircle.common import exceptions
+from tricircle.common import utils
+
+
+class TricircleUtilsTestCase(unittest.TestCase):
+    def test_check_string_length(self):
+        self.assertIsNone(utils.check_string_length(
+                          'test', 'name', max_len=255))
+        self.assertRaises(exceptions.InvalidInput,
+                          utils.check_string_length,
+                          11, 'name', max_len=255)
+        self.assertRaises(exceptions.InvalidInput,
+                          utils.check_string_length,
+                          '', 'name', min_len=1)
+        self.assertRaises(exceptions.InvalidInput,
+                          utils.check_string_length,
+                          'a' * 256, 'name', max_len=255)