Add primitive currency type

sqlalchemy_utils/__init__.py

@@ -54,6 +54,7 @@ from .listeners import (  # noqa
 )
 from .models import Timestamp  # noqa
 from .observer import observes  # noqa
+from .primitives import Currency, WeekDay, WeekDays  # noqa
 from .proxy_dict import proxy_dict, ProxyDict  # noqa
 from .query_chain import QueryChain  # noqa
 from .types import (  # noqa

sqlalchemy_utils/primitives/__init__.py

@@ -1,7 +1,3 @@
-from .weekday import WeekDay
-from .weekdays import WeekDays
-
-__all__ = (
-    WeekDay,
-    WeekDays
-)
+from .currency import Currency  # noqa
+from .weekday import WeekDay  # noqa
+from .weekdays import WeekDays  # noqa

sqlalchemy_utils/primitives/currency.py

@@ -0,0 +1,57 @@
+# -*- coding: utf-8 -*-
+import six
+from babel.numbers import get_currency_symbol
+
+from sqlalchemy_utils import i18n
+from sqlalchemy_utils.utils import str_coercible
+
+
+@str_coercible
+class Currency(object):
+    def __init__(self, code):
+        if isinstance(code, Currency):
+            self.code = code
+        elif isinstance(code, six.string_types):
+            self.validate(code)
+            self.code = code
+        else:
+            raise TypeError(
+                'First argument given to Currency constructor should be '
+                'either an instance of Currency or valid three letter '
+                'currency code.'
+            )
+
+    @classmethod
+    def validate(self, code):
+        try:
+            i18n.get_locale().currencies[code]
+        except KeyError:
+            raise ValueError("{0}' is not valid currency code.")
+
+    @property
+    def symbol(self):
+        return get_currency_symbol(self.code, i18n.get_locale())
+
+    @property
+    def name(self):
+        return i18n.get_locale().currencies[self.code]
+
+    def __eq__(self, other):
+        if isinstance(other, Currency):
+            return self.code == other.code
+        elif isinstance(other, six.string_types):
+            return self.code == other
+        else:
+            return NotImplemented
+
+    def __ne__(self, other):
+        return not (self == other)
+
+    def __hash__(self):
+        return hash(self.code)
+
+    def __repr__(self):
+        return '%s(%r)' % (self.__class__.__name__, self.code)
+
+    def __unicode__(self):
+        return self.name

tests/primitives/test_currency.py

@@ -0,0 +1,66 @@
+# -*- coding: utf-8 -*-
+import six
+from babel import Locale
+from pytest import mark, raises
+
+from sqlalchemy_utils import Currency, i18n
+
+
+class TestCurrency(object):
+    def setup_method(self, method):
+        i18n.get_locale = lambda: Locale('en')
+
+    def test_init(self):
+        assert Currency('USD') == Currency(Currency('USD'))
+
+    def test_hashability(self):
+        assert len(set([Currency('USD'), Currency('USD')])) == 1
+
+    def test_invalid_currency_code(self):
+        with raises(ValueError):
+            Currency('Unknown code')
+
+    def test_invalid_currency_code_type(self):
+        with raises(TypeError):
+            Currency(None)
+
+    @mark.parametrize(
+        ('code', 'name'),
+        (
+            ('USD', 'US Dollar'),
+            ('EUR', 'Euro')
+        )
+    )
+    def test_name_property(self, code, name):
+        assert Currency(code).name == name
+
+    @mark.parametrize(
+        ('code', 'symbol'),
+        (
+            ('USD', u'$'),
+            ('EUR', u'€')
+        )
+    )
+    def test_symbol_property(self, code, symbol):
+        assert Currency(code).symbol == symbol
+
+    def test_equality_operator(self):
+        assert Currency('USD') == 'USD'
+        assert 'USD' == Currency('USD')
+        assert Currency('USD') == Currency('USD')
+
+    def test_non_equality_operator(self):
+        assert Currency('USD') != 'EUR'
+        assert not (Currency('USD') != 'USD')
+
+    def test_unicode(self):
+        currency = Currency('USD')
+        assert six.text_type(currency) == u'US Dollar'
+
+    def test_str(self):
+        currency = Currency('USD')
+        assert str(currency) == 'US Dollar'
+
+    def test_representation(self):
+        currency = Currency('USD')
+        assert repr(currency) == "Currency('USD')"