Country implements ordering (#361)

* Orderable Country

Country needs to be orderable if it is part of the primary key and cascade deletion is in use.

* total ordering added. Using six to determine whether other is string.

* test of Country order operators.

* Fixed buggy order precedence in tests.

* NotImplemented is a returned type and not a thrown exception.

* total_ordering replaces explicit declaration of all order operators.

* Removed implementation check for __le__, __ge__ and __gt__.

* Parametrized test_ordering replaces test_op_operator.

sqlalchemy_utils/primitives/country.py

@@ -1,9 +1,12 @@
+from functools import total_ordering
+
 import six
 
 from .. import i18n
 from ..utils import str_coercible
 
 
+@total_ordering
 @str_coercible
 class Country(object):
     """
@@ -95,6 +98,13 @@ def __hash__(self):
     def __ne__(self, other):
         return not (self == other)
 
+    def __lt__(self, other):
+        if isinstance(other, Country):
+            return self.code < other.code
+        elif isinstance(other, six.string_types):
+            return self.code < other
+        return NotImplemented
+
     def __repr__(self):
         return '%s(%r)' % (self.__class__.__name__, self.code)
 

tests/primitives/test_country.py

@@ -1,3 +1,5 @@
+import operator
+
 import pytest
 import six
 
@@ -56,6 +58,33 @@ def test_non_equality_operator(self):
         assert Country(u'FI') != u'sv'
         assert not (Country(u'FI') != u'FI')
 
+    @pytest.mark.parametrize(
+        'op, code_left, code_right, is_',
+        [
+            (operator.lt, u'ES', u'FI', True),
+            (operator.lt, u'FI', u'ES', False),
+            (operator.lt, u'ES', u'ES', False),
+
+            (operator.le, u'ES', u'FI', True),
+            (operator.le, u'FI', u'ES', False),
+            (operator.le, u'ES', u'ES', True),
+
+            (operator.ge, u'ES', u'FI', False),
+            (operator.ge, u'FI', u'ES', True),
+            (operator.ge, u'ES', u'ES', True),
+
+            (operator.gt, u'ES', u'FI', False),
+            (operator.gt, u'FI', u'ES', True),
+            (operator.gt, u'ES', u'ES', False),
+        ]
+    )
+    def test_ordering(self, op, code_left, code_right, is_):
+        country_left = Country(code_left)
+        country_right = Country(code_right)
+        assert op(country_left, country_right) is is_
+        assert op(country_left, code_right) is is_
+        assert op(code_left, country_right) is is_
+
     def test_hash(self):
         return hash(Country('FI')) == hash('FI')