Added test for Chainable Undefined Behavior

Signed-off-by: Will Haines <william.haines@colorado.edu>

awx_collection/test/awx/test_notification_template.py

@@ -3,7 +3,7 @@ __metaclass__ = type
 
 import pytest
 
-from awx.main.models import NotificationTemplate
+from awx.main.models import NotificationTemplate, Job
 
 
 def compare_with_encrypted(model_config, param_config):
@@ -109,3 +109,32 @@ def test_deprecated_to_modern_no_op(run_module, admin_user, organization):
     ), admin_user)
     assert not result.get('failed', False), result.get('msg', result)
     assert not result.pop('changed', None), result
+
+
+@pytest.mark.django_db
+def test_build_notification_message_undefined(run_module, admin_user, organization):
+    """Job notification templates may encounter undefined values in the context when they are
+    rendered. Make sure that accessing attributes or items of an undefined value returns another
+    instance of Undefined, rather than raising an UndefinedError. This enables the use of expressions
+    like "{{ job.created_by.first_name | default('unknown') }}"."""
+    job = Job.objects.create(name='foobar')
+
+    nt_config = {
+        'url': 'http://www.example.com/hook',
+        'headers': {
+            'X-Custom-Header': 'value123'
+        }
+    }
+    custom_start_template = {'body': '{"started_by": "{{ job.summary_fields.created_by.username | default(\'My Placeholder\') }}"}'}
+    messages = {'started': custom_start_template, 'success': None, 'error': None, 'workflow_approval': None}
+    result = run_module('tower_notification_template', dict(
+        name='foo-notification-template',
+        organization=organization.name,
+        notification_type='webhook',
+        notification_configuration=nt_config,
+        messages=messages,
+    ), admin_user)
+    nt = NotificationTemplate.objects.get(id=result['id'])
+
+    _, body = job.build_notification_message(nt, 'running')
+    assert '{"started_by": "My Placeholder"}' in body