rhn_channel/register: Porting tests to pytest (#33719)

* rhn_channel/register: Porting tests to pytest

Related: #33387

* rhn unit tests: use mock_request as a fixture

test/units/modules/packaging/os/conftest.py

@@ -0,0 +1,29 @@
+from ansible.compat.tests.mock import patch
+from ansible.module_utils.six.moves import xmlrpc_client
+
+import pytest
+
+
+def get_method_name(request_body):
+    return xmlrpc_client.loads(request_body)[1]
+
+
+@pytest.fixture
+def mock_request(request, mocker):
+    responses = request.getfuncargvalue('testcase')['calls']
+    module_name = request.module.TESTED_MODULE
+
+    def transport_request(host, handler, request_body, verbose=0):
+        """Fake request"""
+        method_name = get_method_name(request_body)
+        excepted_name, response = responses.pop(0)
+        if method_name == excepted_name:
+            if isinstance(response, Exception):
+                raise response
+            else:
+                return response
+        else:
+            raise Exception('Expected call: %r, called with: %r' % (excepted_name, method_name))
+
+    target = '{0}.xmlrpc_client.Transport.request'.format(module_name)
+    mocker.patch(target, side_effect=transport_request)