Split out dkim.canonicalization, and test it. Note that test_wsp_strips_headers is correctly failing, as trailing whitespace is not stripped from header names.

dkim/tests/__init__.py

@@ -21,11 +21,13 @@ import unittest
 
 def test_suite():
     from dkim.tests import (
+        test_canonicalization,
         test_crypto,
         test_dkim,
         test_util,
         )
     modules = [
+        test_canonicalization,
         test_crypto,
         test_dkim,
         test_util,

dkim/tests/test_canonicalization.py

@@ -0,0 +1,83 @@
+# This software is provided 'as-is', without any express or implied
+# warranty.  In no event will the author be held liable for any damages
+# arising from the use of this software.
+#
+# Permission is granted to anyone to use this software for any purpose,
+# including commercial applications, and to alter it and redistribute it
+# freely, subject to the following restrictions:
+#
+# 1. The origin of this software must not be misrepresented; you must not
+#    claim that you wrote the original software. If you use this software
+#    in a product, an acknowledgment in the product documentation would be
+#    appreciated but is not required.
+# 2. Altered source versions must be plainly marked as such, and must not be
+#    misrepresented as being the original software.
+# 3. This notice may not be removed or altered from any source distribution.
+#
+# Copyright (c) 2011 William Grant <me@williamgrant.id.au>
+
+import unittest
+
+from dkim.canonicalization import Simple, Relaxed
+
+
+class TestSimpleAlgorithm(unittest.TestCase):
+
+    def test_headers_untouched(self):
+        test_headers = [(b'Foo  ', b'bar\r\n'), (b'Foo', b'baz\r\n')]
+        self.assertEqual(
+            test_headers,
+            Simple.canonicalize_headers(test_headers))
+
+    def test_strips_trailing_empty_lines_from_body(self):
+        self.assertEqual(
+            b'Foo  \tbar    \r\n',
+            Simple.canonicalize_body(
+                b'Foo  \tbar    \r\n\r\n'))
+
+
+class TestRelaxedAlgorithm(unittest.TestCase):
+
+    def test_lowercases_headers(self):
+        self.assertEqual(
+            [(b'foo', b'Bar\r\n'), (b'baz', b'Foo\r\n')],
+            Relaxed.canonicalize_headers(
+                [(b'Foo', b'Bar\r\n'), (b'BaZ', b'Foo\r\n')]))
+
+    def test_unfolds_headers(self):
+        self.assertEqual(
+            [(b'foo', b'Bar baz\r\n')],
+            Relaxed.canonicalize_headers(
+                [(b'Foo', b'Bar\r\n baz\r\n')]))
+
+    def test_wsp_compresses_headers(self):
+        self.assertEqual(
+            [(b'foo', b'Bar baz\r\n')],
+            Relaxed.canonicalize_headers(
+                [(b'Foo', b'Bar \t baz\r\n')]))
+
+    def test_wsp_strips_headers(self):
+        self.assertEqual(
+            [(b'foo', b'Bar baz\r\n')],
+            Relaxed.canonicalize_headers(
+                [(b'Foo  ', b'   Bar \t baz   \r\n')]))
+
+    def test_strips_trailing_wsp_from_body(self):
+        self.assertEqual(
+            b'Foo\r\nbar\r\n',
+            Relaxed.canonicalize_body(b'Foo  \t\r\nbar\r\n'))
+
+    def test_wsp_compresses_body(self):
+        self.assertEqual(
+            b'Foo bar\r\n',
+            Relaxed.canonicalize_body(b'Foo  \t  bar\r\n'))
+
+    def test_strips_trailing_empty_lines_from_body(self):
+        self.assertEqual(
+            b'Foo\r\nbar\r\n',
+            Relaxed.canonicalize_body(b'Foo\r\nbar\r\n\r\n\r\n'))
+
+
+def test_suite():
+    from unittest import TestLoader
+    return TestLoader().loadTestsFromName(__name__)