[sonic-config-engine]: Fix ndppd.conf test

Signed-off-by: Lawrence Lee <[email protected]>

src/sonic-config-engine/tests/sample_output/ndppd.conf → src/sonic-config-engine/tests/sample_output/py2/ndppd.conf

@@ -6,15 +6,15 @@
 # See man page for ndppd.conf.5 for descriptions of all available options
 
 proxy Vlan1000 {
-    rule fc01:1000::/64 {
-        static
-    }
     rule fc02:1000::/64 {
         static
     }
     rule fc03:1000::/64 {
         static
     }
+    rule fc01:1000::/64 {
+        static
+    }
 }
 
 proxy Vlan2000 {

src/sonic-config-engine/tests/sample_output/py3/ndppd.conf

@@ -0,0 +1,25 @@
+# =========== Managed by sonic-cfggen -- DO NOT edit manually! ====================
+# Generated by /usr/share/sonic/templates/ndppd.conf.j2 using config DB data
+# File: /etc/ndppd.conf
+#
+# Config file for ndppd, the NDP Proxy Daemon
+# See man page for ndppd.conf.5 for descriptions of all available options
+
+proxy Vlan1000 {
+    rule fc02:1000::/64 {
+        static
+    }
+    rule fc03:1000::/64 {
+        static
+    }
+    rule fc01:1000::/64 {
+        static
+    }
+}
+
+proxy Vlan2000 {
+    rule fc01:2000::/64 {
+        static
+    }
+}
+

src/sonic-config-engine/tests/test_j2files.py

@@ -171,14 +171,11 @@ def test_ipinip_multi_asic(self):
     def test_ndppd_conf(self):
         conf_template = os.path.join(self.test_dir, "ndppd.conf.j2")
         vlan_interfaces_json = os.path.join(self.test_dir, "data", "ndppd", "vlan_interfaces.json")
-        expected = os.path.join(self.test_dir, "sample_output", "ndppd.conf")
+        expected = os.path.join(self.test_dir, "sample_output", utils.PYvX_DIR, "ndppd.conf")
 
         argument = '-j {} -t {} > {}'.format(vlan_interfaces_json, conf_template, self.output_file)
         self.run_script(argument)
-        f = open(self.output_file)
-        contents = f.read()
-        f.close()
-        assert filecmp.cmp(expected, self.output_file), contents
+        assert filecmp.cmp(expected, self.output_file), self.run_diff(expected, self.output_file)
 
 
     def tearDown(self):