Add unit tests for loopbacks; While here, fix a bug in get_by_name(), yaay

unittest/test_loopback.yaml

@@ -0,0 +1,12 @@
+loopbacks:
+  loop0:
+    description: "Loopback, no config"
+  loop1:
+    description: "Loopback, both LCP and address"
+    mtu: 2000
+    lcp: "loop56789012345"
+    addresses: [ 192.0.2.1/29, 2001:db8::1/64 ]
+  loop2:
+    description: "Loopback, invalid because it has an address but no LCP"
+    mtu: 2000
+    addresses: [ 192.0.2.9/29, 2001:db8:1::1/64 ]

validator/loopback.py

@@ -19,6 +19,14 @@ class NullHandler(logging.Handler):
     def emit(self, record):
         pass
 
+def get_loopbacks(yaml):
+    """ Return a list of all loopbacks. """
+    ret = []
+    if 'loopbacks' in yaml:
+        for ifname, iface in yaml['loopbacks'].items():
+            ret.append(ifname)
+    return ret
+
 def get_by_name(yaml, ifname):
     """ Return the loopback by name, if it exists. Return None otherwise. """
     try:
@@ -26,7 +34,7 @@ def get_by_name(yaml, ifname):
             return ifname, yaml['loopbacks'][ifname]
     except:
         pass
-    return None
+    return None, None
 
 
 def validate_loopbacks(yaml):

validator/test_loopback.py

@@ -0,0 +1,26 @@
+import unittest
+import yaml
+import validator.loopback as loopback
+
+class TestLoopbackMethods(unittest.TestCase):
+    def setUp(self):
+        with open("unittest/test_loopback.yaml", "r") as f:
+            self.cfg = yaml.load(f, Loader = yaml.FullLoader)
+
+    def test_get_by_name(self):
+        ifname, iface = loopback.get_by_name(self.cfg, "loop1")
+        self.assertIsNotNone(iface)
+        self.assertEqual("loop1", ifname)
+        self.assertEqual(iface['mtu'], 2000)
+
+        ifname, iface = loopback.get_by_name(self.cfg, "loop-noexist")
+        self.assertIsNone(ifname)
+        self.assertIsNone(iface)
+
+    def test_enumerators(self):
+        ifs = loopback.get_loopbacks(self.cfg)
+        self.assertEqual(len(ifs), 3)
+        self.assertIn("loop0", ifs)
+        self.assertIn("loop1", ifs)
+        self.assertIn("loop2", ifs)
+        self.assertNotIn("loop-noexist", ifs)