Introduce tests for yaql structures

We use yaql in many hot templates, but they are usually faily obscure
and not documented, which makes it hard to change them over time (to
make them perform better for example).

This introduces some basic infrastructure for testing them, as well as a
first modification to show how things would be easier to change.

Change-Id: I1a8d3a514d8fa0de4b024d3ae320723d791f3e7d

puppet/services/apache.yaml

@@ -62,10 +62,9 @@ resources:
         # certificates for those. We skip the tenant network since
         # we don't need a certificate for that.
         yaql:
-          expression: list($.data.map.items().map($1[1])).distinct().where($ != tenant)
+          expression: list($.data.values().toSet().where($ != tenant))
           data:
-            map:
-              get_param: ServiceNetMap
+            get_param: ServiceNetMap
 
 outputs:
   role_data:

test-requirements.txt

@@ -15,3 +15,4 @@ testscenarios>=0.4 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT
 mock>=2.0.0 # BSD
 oslotest>=3.2.0 # Apache-2.0
+yaql>=1.1.3 # Apache 2.0 License

tripleo_heat_templates/tests/test_yaql.py

@@ -0,0 +1,45 @@
+# Copyright 2018 Red Hat 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.
+
+import io
+import tempfile
+
+import mock
+from oslotest import base
+import six
+import testscenarios
+import yaml
+import yaql
+
+
+class YAQLTestCase(base.BaseTestCase):
+
+    def get_snippet(self, template, path):
+        with open(template) as f:
+            template = f.read()
+            data = yaml.safe_load(template)
+            for i in path.split('.'):
+                data = data[i]
+            return data['yaql']['expression']
+
+    def test_apache_networks(self):
+        snippet = self.get_snippet(
+            'puppet/services/apache.yaml',
+            'resources.ApacheNetworks.properties.value')
+        self.assertEqual(
+            ['service'],
+            yaql.eval(
+                snippet,
+                {'data': {'nova': 'tenant', 'cinder': 'service',
+                          'glance': 'service'}}))