test: add test to verify RequiredForOnline= setting with ActivationPolicy=

Add test to verify that the RequiredForOnline= value is correct based on
the configuration of ActivationPolicy=

test/test-network/conf/25-activation-policy.network.d/bound.conf

@@ -0,0 +1,5 @@
+[Link]
+ActivationPolicy=bound
+
+[Network]
+BindCarrier=dummy98

test/test-network/conf/25-activation-policy.network.d/required-no.conf

@@ -0,0 +1,2 @@
+[Link]
+RequiredForOnline=no

test/test-network/conf/25-activation-policy.network.d/required-yes.conf

@@ -0,0 +1,2 @@
+[Link]
+RequiredForOnline=yes

test/test-network/systemd-networkd-tests.py

@@ -1793,6 +1793,7 @@ class NetworkdNetworkTests(unittest.TestCase, Utilities):
     units = [
         '11-dummy.netdev',
         '12-dummy.netdev',
+        '12-dummy.network',
         '23-active-slave.network',
         '24-keep-configuration-static.network',
         '24-search-domain.network',
@@ -2801,6 +2802,50 @@ class NetworkdNetworkTests(unittest.TestCase, Utilities):
             with self.subTest(test=test):
                 self._test_activation_policy(test)
 
+    def _test_activation_policy_required_for_online(self, policy, required):
+        self.setUp()
+        conffile = '25-activation-policy.network'
+        units = ['11-dummy.netdev', '12-dummy.netdev', '12-dummy.network', conffile]
+        if policy:
+            units += [f'{conffile}.d/{policy}.conf']
+        if required:
+            units += [f'{conffile}.d/required-{required}.conf']
+        copy_unit_to_networkd_unit_path(*units, dropins=False)
+        start_networkd()
+
+        if policy.endswith('down') or policy == 'manual':
+            self.wait_operstate('test1', 'off', setup_state='configuring')
+        else:
+            self.wait_online(['test1'])
+
+        if policy == 'always-down':
+            # if always-down, required for online is forced to no
+            expected = False
+        elif required:
+            # otherwise if required for online is specified, it should match that
+            expected = required == 'yes'
+        elif policy:
+            # otherwise if only policy specified, required for online defaults to
+            # true if policy is up, always-up, or bound
+            expected = policy.endswith('up') or policy == 'bound'
+        else:
+            # default is true, if neither are specified
+            expected = True
+
+        output = check_output(*networkctl_cmd, '-n', '0', 'status', 'test1', env=env)
+        print(output)
+
+        yesno = 'yes' if expected else 'no'
+        self.assertRegex(output, f'Required For Online: {yesno}')
+
+        self.tearDown()
+
+    def test_activation_policy_required_for_online(self):
+        for policy in ['up', 'always-up', 'manual', 'always-down', 'down', 'bound', '']:
+            for required in ['yes', 'no', '']:
+                with self.subTest(policy=policy, required=required):
+                    self._test_activation_policy_required_for_online(policy, required)
+
     def test_domain(self):
         copy_unit_to_networkd_unit_path('12-dummy.netdev', '24-search-domain.network')
         start_networkd()