Fix relative path for default templates

After installing package we have a problem with running tests
from default templates.
closes-bug: 1569826

Co-Authored-By: Luigi Toscano <ltoscano@redhat.com>

Change-Id: I879c63b65b6f89a77acd672eea9d1c16d42f1a1b

releasenotes/notes/fix-installed-resource-discovery-36ffa157cf9b06b9.yaml

@@ -0,0 +1,6 @@
+---
+prelude: >
+    Fix default resource discovery from the installed package.
+fixes:
+  - The default set of resources (test templates for each plugin, etc)
+    can now be properly discovered when the package is installed.

sahara_tests/scenario/runner.py

@@ -25,18 +25,24 @@ import tempfile
 
 from mako import template as mako_template
 from oslo_utils import fileutils
+import pkg_resources as pkg
 import six
 import yaml
 
 from sahara_tests.scenario import validation
+from sahara_tests import version
 
 
-TEST_TEMPLATE_DIR = 'sahara_tests/scenario/defaults/'
+SCENARIO_RESOURCES_DIR = pkg.resource_filename(version.version_info.package,
+                                               'scenario')
+
+TEST_TEMPLATE_DIR = os.path.join(SCENARIO_RESOURCES_DIR, 'defaults/')
 DEFAULT_TEMPLATE_VARS = [os.path.join(TEST_TEMPLATE_DIR,
                                       'credentials.yaml.mako'),
                          os.path.join(TEST_TEMPLATE_DIR,
                                       'edp.yaml.mako')]
-TEST_TEMPLATE_PATH = 'sahara_tests/scenario/testcase.py.mako'
+TEST_TEMPLATE_PATH = os.path.join(SCENARIO_RESOURCES_DIR,
+                                  'testcase.py.mako')
 
 
 def set_defaults(config):

sahara_tests/version.py

@@ -0,0 +1,18 @@
+# Copyright (c) 2016 Mirantis Inc.
+#
+# 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.
+
+from pbr import version
+
+version_info = version.VersionInfo('sahara_tests')