[PATCH v3 12/20] avocado/tasst: Add helper for getting MTU of a network interface

[David Gibson <david@gibson.dropbear.id.au>]

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 avocado/tasst/meta/veth.py | 5 +++++
 avocado/tasst/site.py      | 9 +++++++++
 2 files changed, 14 insertions(+)

diff --git a/avocado/tasst/meta/veth.py b/avocado/tasst/meta/veth.py
index c4cdcf7..301ccb9 100644
--- a/avocado/tasst/meta/veth.py
+++ b/avocado/tasst/meta/veth.py
@@ -41,3 +41,8 @@ class VethTasst(Tasst):
         with self.setup_veth() as (ns1, ns2):
             self.assertCountEqual(ns1.ifs(), ['lo', 'veth1'])
             self.assertCountEqual(ns2.ifs(), ['lo', 'veth2'])
+
+    def test_mtu(self):
+        with self.setup_veth() as (ns1, ns2):
+            self.assertEquals(ns1.mtu('veth1'), 1500)
+            self.assertEquals(ns2.mtu('veth2'), 1500)
diff --git a/avocado/tasst/site.py b/avocado/tasst/site.py
index 3cb3721..f19a3fc 100644
--- a/avocado/tasst/site.py
+++ b/avocado/tasst/site.py
@@ -61,6 +61,11 @@ class Site(contextlib.AbstractContextManager):
         self.require_cmds('ip')
         self.fg('ip link set {} up'.format(ifname), sudo=True)
 
+    def mtu(self, ifname):
+        self.require_cmds('ip')
+        (info,) = json.loads(self.output('ip -j link show {}'.format(ifname)))
+        return info['mtu']
+
     def addrinfos(self, ifname, **filter):
         self.require_cmds('ip')
         info = json.loads(self.output('ip -j addr show {}'.format(ifname)))
@@ -129,6 +134,10 @@ class SiteTasst(Tasst):
                         for a in ['127.0.0.1/8', '::1/128']]
             self.assertCountEqual(site.addrs('lo'), expected)
 
+    def test_lo_mtu(self):
+        with self.setup_site() as site:
+            self.assertEqual(site.mtu('lo'), 65536)
+
 
 class IsolatedSiteTasst(SiteTasst):
     """
-- 
@@ -61,6 +61,11 @@ class Site(contextlib.AbstractContextManager):
         self.require_cmds('ip')
         self.fg('ip link set {} up'.format(ifname), sudo=True)
 
+    def mtu(self, ifname):
+        self.require_cmds('ip')
+        (info,) = json.loads(self.output('ip -j link show {}'.format(ifname)))
+        return info['mtu']
+
     def addrinfos(self, ifname, **filter):
         self.require_cmds('ip')
         info = json.loads(self.output('ip -j addr show {}'.format(ifname)))
@@ -129,6 +134,10 @@ class SiteTasst(Tasst):
                         for a in ['127.0.0.1/8', '::1/128']]
             self.assertCountEqual(site.addrs('lo'), expected)
 
+    def test_lo_mtu(self):
+        with self.setup_site() as site:
+            self.assertEqual(site.mtu('lo'), 65536)
+
 
 class IsolatedSiteTasst(SiteTasst):
     """
-- 
2.40.1