NSX|v+v3+p: Allow resetting port binding host

Change-Id: Ic9f3f080bbf51a04cea601b2c4b0614b9b5c4e33

vmware_nsx/db/nsx_portbindings_db.py

@@ -95,6 +95,11 @@ class NsxPortBindingMixin(pbin_db.PortBindingMixin):
     def _process_portbindings_create_and_update(
         self, context, port, port_res,
         vif_type=nsx_constants.VIF_TYPE_DVS):
+
+        # Allow clearing the host id
+        if pbin.HOST_ID in port and port[pbin.HOST_ID] is None:
+            port[pbin.HOST_ID] = ''
+
         super(NsxPortBindingMixin,
               self)._process_portbindings_create_and_update(
                   context, port, port_res)

vmware_nsx/tests/unit/nsx_v3/test_plugin.py

@@ -1929,6 +1929,22 @@ class TestPortsV2(common_v3.NsxV3SubnetMixin,
     def test_requested_subnet_id_v4_and_v6(self):
         return super(TestPortsV2, self).test_requested_subnet_id_v4_and_v6()
 
+    def test_port_binding_host(self):
+        with self.port() as port:
+            # add host
+            data = {'port': {portbindings.HOST_ID: 'abc'}}
+            req = self.new_update_request('ports',
+                                          data, port['port']['id'])
+            res = self.deserialize('json', req.get_response(self.api))
+            self.assertEqual('abc', res['port'][portbindings.HOST_ID])
+
+            # remove host
+            data = {'port': {portbindings.HOST_ID: None}}
+            req = self.new_update_request('ports',
+                                          data, port['port']['id'])
+            res = self.deserialize('json', req.get_response(self.api))
+            self.assertEqual('', res['port'][portbindings.HOST_ID])
+
 
 class DHCPOptsTestCase(test_dhcpopts.TestExtraDhcpOpt,
                        NsxV3PluginTestCaseMixin):