test:common: fixup merging of gateway tests

tests/generator/test_common.py

@@ -571,7 +571,41 @@ def test_eth_ignore_carrier_true(self):
 ConfigureWithoutCarrier=yes
 '''})
 
-    def test_gateway(self):
+    def test_gateway4(self):
+        err = self.generate('''network:
+  version: 2
+  ethernets:
+    engreen:
+      addresses: ["192.168.14.2/24"]
+      gateway4: 192.168.14.1''')
+        self.assertIn("`gateway4` has been deprecated, use default routes instead.", err)
+        self.assert_networkd({'engreen.network': '''[Match]
+Name=engreen
+
+[Network]
+LinkLocalAddressing=ipv6
+Address=192.168.14.2/24
+Gateway=192.168.14.1
+'''})
+
+    def test_gateway6(self):
+        err = self.generate('''network:
+  version: 2
+  ethernets:
+    engreen:
+      addresses: ["2001:FFfe::1/64"]
+      gateway6: 2001:FFfe::2''')
+        self.assertIn("`gateway6` has been deprecated, use default routes instead.", err)
+        self.assert_networkd({'engreen.network': '''[Match]
+Name=engreen
+
+[Network]
+LinkLocalAddressing=ipv6
+Address=2001:FFfe::1/64
+Gateway=2001:FFfe::2
+'''})
+
+    def test_gateway_full(self):
         self.generate('''network:
   version: 2
   ethernets: