url lookup - set default user agent (#72324)

* Add unit tests
* Add note about when default changed

changelogs/fragments/url-lookup-add-httpagent.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - url lookup - set default user agent to ``ansible-httpget`` (https://github.com/ansible/ansible/pull/72324)

lib/ansible/plugins/lookup/url.py

@@ -64,9 +64,10 @@ options:
         - section: url_lookup
           key: timeout
   http_agent:
-    description: User-Agent to use in the request
+    description: User-Agent to use in the request. The default was changed in 2.11 to C(ansible-httpget).
     type: string
     version_added: "2.10"
+    default: ansible-httpget
     vars:
         - name: ansible_lookup_url_agent
     env:

test/units/plugins/lookup/test_url.py

@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+# Copyright: (c) 2020, Sam Doran <sdoran@redhat.com>
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+import pytest
+
+from ansible.plugins.loader import lookup_loader
+
+
+@pytest.mark.parametrize(
+    ('kwargs', 'agent'),
+    (
+        ({}, 'ansible-httpget'),
+        ({'http_agent': 'SuperFox'}, 'SuperFox'),
+    )
+)
+def test_user_agent(mocker, kwargs, agent):
+    mock_open_url = mocker.patch('ansible.plugins.lookup.url.open_url', side_effect=AttributeError('raised intentionally'))
+    url_lookup = lookup_loader.get('url')
+    with pytest.raises(AttributeError):
+        url_lookup.run(['https://nourl'], **kwargs)
+    assert 'http_agent' in mock_open_url.call_args.kwargs
+    assert mock_open_url.call_args.kwargs['http_agent'] == agent