ethernet: T3163: not all NIC drivers support ring-buffer configuration

In addition to commit cf1156a60e ("ethernet: T3163: probe driver for maximum
rx/tx ring-buffer size") this extends the logic in a way as not every driver
supports setting the buffers at all so it will properly error out.

When invoking "ethtool -g" both stdout and stderr are captured and no exception
is raised if it's an unsupported driver feature. The verify() section will
inform the user about the illegal operation.

1 files changed, 33 insertions, 0 deletions

diff --git a/src/tests/test_ethtool.py b/src/tests/test_ethtool.py
new file mode 100644
index 000000000..bc53b938a
--- /dev/null
+++ b/src/tests/test_ethtool.py
@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from unittest import TestCase
+from vyos.ethtool import Ethtool
+
+class TestVyOSEthtool(TestCase):
+    def test_ring_buffer(self):
+        tmp = Ethtool('lo')
+        self.assertEqual(tmp.get_rx_buffer(), None)
+        self.assertEqual(tmp.get_tx_buffer(), None)
+
+    def test_fixed_settings(self):
+        tmp = Ethtool('lo')
+        self.assertTrue(tmp.is_fixed_lro())
+        self.assertFalse(tmp.is_fixed_gro())
+        self.assertFalse(tmp.is_fixed_gso())
+        self.assertFalse(tmp.is_fixed_sg())
+
+