Allow MPLS on loopbacks too -- needed for BVIs and such. Add tests.

vppcfg/config/loopback.py

@@ -96,3 +96,14 @@ def validate_loopbacks(yaml):
             result = False
 
     return result, msgs
+
+
+def is_mpls(yaml, ifname):
+    """Returns True if the loopback exists and has mpls enabled. Returns false otherwise."""
+    ifname, iface = get_by_name(yaml, ifname)
+    try:
+        if iface["mpls"] == True:
+            return True
+    except:
+        pass
+    return False

vppcfg/config/test_loopback.py

@@ -50,3 +50,8 @@ class TestLoopbackMethods(unittest.TestCase):
         self.assertIn("loop1", ifs)
         self.assertIn("loop2", ifs)
         self.assertNotIn("loop-noexist", ifs)
+
+    def test_is_mpls(self):
+        self.assertTrue(loopback.is_mpls(self.cfg, "loop1"))
+        self.assertFalse(loopback.is_mpls(self.cfg, "loop2"))
+        self.assertFalse(loopback.is_mpls(self.cfg, "loop-noexist"))