Sketch an implementation of I18N.

src/hamcrest/core/__init__.py

@@ -1,5 +1,6 @@
 from hamcrest.core.assert_that import assert_that
 from hamcrest.core.core import *
+from hamcrest.core.locale import set_locale, get_locale
 
 __author__ = "Jon Reid"
 __copyright__ = "Copyright 2011 hamcrest.org"

src/hamcrest/core/assert_that.py

@@ -1,8 +1,9 @@
 import warnings
 from typing import Optional, TypeVar, cast, overload
 
+from hamcrest.core.locale import get_locale
 from hamcrest.core.matcher import Matcher
-from hamcrest.core.string_description import StringDescription
+from hamcrest.core.localized_description import LocalizedDescription
 
 __author__ = "Jon Reid"
 __copyright__ = "Copyright 2011 hamcrest.org"
@@ -64,10 +65,10 @@ def assert_that(actual, matcher=None, reason=""):
 
 def _assert_match(actual: T, matcher: Matcher[T], reason: str) -> None:
     if not matcher.matches(actual):
-        description = StringDescription()
-        description.append_text(reason).append_text("\nExpected: ").append_description_of(
-            matcher
-        ).append_text("\n     but: ")
+        description = LocalizedDescription(locale=get_locale())
+        description.append_text(reason).append_text("\n") \
+            .append_text("Expected: ").append_description_of(matcher) \
+            .append_text("\n").append_text("     but: ")
         matcher.describe_mismatch(actual, description)
         description.append_text("\n")
         raise AssertionError(description)

src/hamcrest/core/base_matcher.py

@@ -2,7 +2,7 @@
 
 from hamcrest.core.description import Description
 from hamcrest.core.matcher import Matcher
-from hamcrest.core.string_description import tostring
+from hamcrest.core.localized_description import tostring
 
 __author__ = "Jon Reid"
 __copyright__ = "Copyright 2011 hamcrest.org"

src/hamcrest/core/locale.py

@@ -0,0 +1,41 @@
+__author__ = "Majority Judgment"
+__copyright__ = "Copyright 2011 hamcrest.org"
+__license__ = "BSD, see License.txt"
+
+
+_locale = "en_US"
+
+
+def set_locale(new_locale):
+    global _locale  # :(|)
+    _locale = new_locale
+
+
+def get_locale():
+    global _locale  # :(|)
+    return _locale
+
+
+class LocaleLazyLoader(object):
+
+    # FIXME
+    # locales = dict()
+    locales = {
+        'fr_FR': {
+            'Butterfly': 'Papillon',
+            'ENGLISH DESCRIPTION': 'DESCRIPTION FRANÇAISE',
+
+            'Assertion failed': "Échec d'une assertion",
+            'Expected: ': 'Attendu⋅e: ',
+            '     but: ': '     mais: ',
+            'was ': "obtenu⋅e ",
+        },
+    }
+
+    def get_locale_map(self, locale):
+        if locale not in self.locales:
+            self.locales[locale] = dict()
+        return self.locales[locale]
+
+
+locale_loader = LocaleLazyLoader()

src/hamcrest/core/localized_description.py

@@ -0,0 +1,40 @@
+from typing import Any, Iterable
+
+from hamcrest.core.description import Description
+from hamcrest.core.locale import get_locale, locale_loader
+from hamcrest.core.selfdescribing import SelfDescribing
+from hamcrest.core.string_description import StringDescription
+
+__author__ = "Majority Judgment"
+__copyright__ = "Copyright 2011 hamcrest.org"
+__license__ = "BSD, see License.txt"
+
+
+def tostring(selfdescribing: SelfDescribing) -> str:
+    """Returns the description of a
+    :py:class:`~hamcrest.core.selfdescribing.SelfDescribing` object as a
+    localized string.
+
+    :param selfdescribing: The object to be described.
+    :returns: The description of the object.
+    """
+    return str(LocalizedDescription().append_description_of(selfdescribing))
+
+
+class LocalizedDescription(StringDescription):
+    """Implementation of a localized :py:class:`~hamcrest.core.description.Description`
+    implementations.
+    """
+
+    def __init__(self, locale=None) -> None:
+        super().__init__()
+        if locale is None:
+            locale = get_locale()
+        self.locale = locale
+        self.locale_map = locale_loader.get_locale_map(self.locale)
+
+    def append_text(self, text: str) -> Description:
+        if text in self.locale_map:
+            text = self.locale_map[text]
+        self.append(text)
+        return self

src/hamcrest/library/integration/match_equality.py

@@ -2,7 +2,7 @@
 
 from hamcrest.core.helpers.wrap_matcher import wrap_matcher
 from hamcrest.core.matcher import Matcher
-from hamcrest.core.string_description import tostring
+from hamcrest.core.localized_description import tostring
 
 __author__ = "Chris Rose"
 __copyright__ = "Copyright 2011 hamcrest.org"

src/hamcrest/library/object/hasproperty.py

@@ -6,8 +6,8 @@
 from hamcrest.core.core.allof import AllOf
 from hamcrest.core.description import Description
 from hamcrest.core.helpers.wrap_matcher import wrap_matcher as wrap_shortcut
+from hamcrest.core.localized_description import LocalizedDescription
 from hamcrest.core.matcher import Matcher
-from hamcrest.core.string_description import StringDescription
 
 __author__ = "Chris Rose"
 __copyright__ = "Copyright 2011 hamcrest.org"
@@ -54,7 +54,7 @@ def describe_mismatch(self, item: object, mismatch_description: Description) ->
         self.value_matcher.describe_mismatch(value, mismatch_description)
 
     def __str__(self):
-        d = StringDescription()
+        d = LocalizedDescription()
         self.describe_to(d)
         return str(d)
 
@@ -178,7 +178,7 @@ def has_properties(*keys_valuematchers, **kv_args):
         base_dict[key] = wrap_shortcut(value)
 
     if len(base_dict) > 1:
-        description = StringDescription().append_text("an object with properties ")
+        description = LocalizedDescription().append_text("an object with properties ")
         for i, (property_name, property_value_matcher) in enumerate(sorted(base_dict.items())):
             description.append_description_of(property_name).append_text(
                 " matching "

tests/hamcrest_unit_test/localized_description_test.py

@@ -0,0 +1,61 @@
+import re
+import unittest
+import pytest
+
+from hamcrest.core.selfdescribing import SelfDescribing
+from hamcrest.core.string_description import *
+from hamcrest.core.localized_description import *
+
+
+__author__ = "Majority Judgment"
+__copyright__ = "Copyright 2011 hamcrest.org"
+__license__ = "BSD, see License.txt"
+
+
+class FakeSelfDescribing(SelfDescribing):
+    def describe_to(self, description):
+        description.append_text("ENGLISH DESCRIPTION")
+
+
+class LocalizedDescriptionTest(unittest.TestCase):
+    def setUp(self):
+        self.description = LocalizedDescription(locale='fr_FR')
+
+    def testLetsSelfDescribingObjectDescribeItself(self):
+        self.description.append_description_of(FakeSelfDescribing())
+        self.assertEqual("DESCRIPTION FRANÇAISE", str(self.description))
+
+    def testNoL10nWhenDescribesStringInQuotes(self):
+        self.description.append_description_of("Butterfly")
+        self.assertEqual("'Butterfly'", str(self.description))
+
+    def testNoL10nWhenSelfDescribingObjectInAngleBrackets(self):
+        self.description.append_description_of(42)
+        self.assertEqual("<42>", str(self.description))
+
+    def testShouldNotAddAngleBracketsIfObjectDescriptionAlreadyHasThem(self):
+        self.description.append_description_of(object())
+        expected = re.compile("<object object at 0x[0-9a-fA-F]+>")
+        self.assertTrue(expected.match(str(self.description)))
+
+    def testDescribeUnicodeStringAsUnicode(self):
+        self.description.append_description_of("\u05d0")
+        self.assertEqual("'\u05d0'", str(self.description))
+
+
+# below is a set of things that should append without error to string
+# descriptions
+@pytest.mark.parametrize("valid_input", (b"bytes", "unicode"))
+def test_description_append_valid_input(valid_input):
+    desc = LocalizedDescription()
+    desc.append(valid_input)
+    str(desc)
+
+
+def test_description_append_invalid_input():
+    desc = LocalizedDescription()
+    desc.append(chr(239))
+
+
+if __name__ == "__main__":
+    unittest.main()