Add 'convert_to_string' and apply for firewall-rule

I7b4108772e8370e8f51971caf40ecd23e9f977e9 has been merged but missing
converter for firewall_rule.  This commit adds a new converter to modify
string and applies this one for following attributes both fwaas and
fwaas_v2.

    * source_port as in firewall_rule
    * destination_port as in firewall_rule

Change-Id: Iced5a588b2618735cbe6fc081e42e49896d7a91a

neutron_lib/api/converters.py

@@ -252,3 +252,14 @@ def convert_to_protocol(data):
             raise n_exc.InvalidInput(error_message=error_message)
     except n_exc.InvalidInput:
         raise n_exc.InvalidInput(error_message=error_message)
+
+
+def convert_to_string(data):
+    """Convert a data value into a string.
+
+    :param data: The data value to convert to a string.
+    :returns: The string value of 'data' if data is not None
+    """
+
+    if data is not None:
+        return str(data)

neutron_lib/api/definitions/firewall.py

@@ -83,9 +83,11 @@ RESOURCE_ATTRIBUTE_MAP = {
                                    'is_visible': True, 'default': None},
         'source_port': {'allow_post': True, 'allow_put': True,
                         'validate': {'type:port_range': None},
+                        'convert_to': converters.convert_to_string,
                         'default': None, 'is_visible': True},
         'destination_port': {'allow_post': True, 'allow_put': True,
                              'validate': {'type:port_range': None},
+                             'convert_to': converters.convert_to_string,
                              'default': None, 'is_visible': True},
         'position': {'allow_post': False, 'allow_put': False,
                      'default': None, 'is_visible': True},

neutron_lib/api/definitions/firewall_v2.py

@@ -84,9 +84,11 @@ RESOURCE_ATTRIBUTE_MAP = {
                                    'is_visible': True, 'default': None},
         'source_port': {'allow_post': True, 'allow_put': True,
                         'validate': {'type:port_range': None},
+                        'convert_to': converters.convert_to_string,
                         'default': None, 'is_visible': True},
         'destination_port': {'allow_post': True, 'allow_put': True,
                              'validate': {'type:port_range': None},
+                             'convert_to': converters.convert_to_string,
                              'default': None, 'is_visible': True},
         'position': {'allow_post': False, 'allow_put': False,
                      'default': None, 'is_visible': True},

neutron_lib/tests/unit/api/test_conversions.py

@@ -270,3 +270,31 @@ class TestConvertProtocol(base.BaseTestCase):
     def test_unknown_string(self):
         with testtools.ExpectedException(n_exc.InvalidInput):
             converters.convert_to_protocol("Invalid")
+
+
+class TestConvertToString(base.BaseTestCase):
+
+    def test_data_is_string(self):
+        self.assertEqual('10000', converters.convert_to_string('10000'))
+
+    def test_data_is_integer(self):
+        self.assertEqual('10000', converters.convert_to_string(10000))
+
+    def test_data_is_integer_zero(self):
+        self.assertEqual('0', converters.convert_to_string(0))
+
+    def test_data_is_none(self):
+        self.assertIsNone(converters.convert_to_string(None))
+
+    def test_data_is_empty_list(self):
+        self.assertEqual('[]', converters.convert_to_string([]))
+
+    def test_data_is_list(self):
+        self.assertEqual("[1, 2, 3]", converters.convert_to_string([1, 2, 3]))
+
+    def test_data_is_empty_dict(self):
+        self.assertEqual('{}', converters.convert_to_string({}))
+
+    def test_data_is_dict(self):
+        self.assertEqual("{'foo': 'bar'}",
+                         converters.convert_to_string({'foo': 'bar'}))

releasenotes/notes/add-convert-to-string-524541aa6224f66f.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    A new converter ``convert_to_string`` into ``neutron_lib.api.converters``.
+    This method can convert an argument which is not None into string value.