1 files changed, 67 insertions, 0 deletions
diff --git a/python/rsa/tests/test_transform.py b/python/rsa/tests/test_transform.py
new file mode 100644
index 0000000000..ffd9ec892a
--- /dev/null
+++ b/python/rsa/tests/test_transform.py
@@ -0,0 +1,67 @@
+# -*- coding: utf-8 -*-
+
+
+import unittest2
+from rsa._compat import b
+from rsa.transform import int2bytes, bytes2int, _int2bytes
+
+
+class Test_int2bytes(unittest2.TestCase):
+    def test_accuracy(self):
+        self.assertEqual(int2bytes(123456789), b('\x07[\xcd\x15'))
+        self.assertEqual(_int2bytes(123456789), b('\x07[\xcd\x15'))
+
+    def test_codec_identity(self):
+        self.assertEqual(bytes2int(int2bytes(123456789, 128)), 123456789)
+        self.assertEqual(bytes2int(_int2bytes(123456789, 128)), 123456789)
+
+    def test_chunk_size(self):
+        self.assertEqual(int2bytes(123456789, 6), b('\x00\x00\x07[\xcd\x15'))
+        self.assertEqual(int2bytes(123456789, 7),
+                         b('\x00\x00\x00\x07[\xcd\x15'))
+
+        self.assertEqual(_int2bytes(123456789, 6),
+                         b('\x00\x00\x07[\xcd\x15'))
+        self.assertEqual(_int2bytes(123456789, 7),
+                         b('\x00\x00\x00\x07[\xcd\x15'))
+
+    def test_zero(self):
+        self.assertEqual(int2bytes(0, 4), b('\x00') * 4)
+        self.assertEqual(int2bytes(0, 7), b('\x00') * 7)
+        self.assertEqual(int2bytes(0), b('\x00'))
+
+        self.assertEqual(_int2bytes(0, 4), b('\x00') * 4)
+        self.assertEqual(_int2bytes(0, 7), b('\x00') * 7)
+        self.assertEqual(_int2bytes(0), b('\x00'))
+
+    def test_correctness_against_base_implementation(self):
+        # Slow test.
+        values = [
+            1 << 512,
+            1 << 8192,
+            1 << 77,
+        ]
+        for value in values:
+            self.assertEqual(int2bytes(value), _int2bytes(value),
+                             "Boom %d" % value)
+            self.assertEqual(bytes2int(int2bytes(value)),
+                             value,
+                             "Boom %d" % value)
+            self.assertEqual(bytes2int(_int2bytes(value)),
+                             value,
+                             "Boom %d" % value)
+
+    def test_raises_OverflowError_when_chunk_size_is_insufficient(self):
+        self.assertRaises(OverflowError, int2bytes, 123456789, 3)
+        self.assertRaises(OverflowError, int2bytes, 299999999999, 4)
+
+        self.assertRaises(OverflowError, _int2bytes, 123456789, 3)
+        self.assertRaises(OverflowError, _int2bytes, 299999999999, 4)
+
+    def test_raises_ValueError_when_negative_integer(self):
+        self.assertRaises(ValueError, int2bytes, -1)
+        self.assertRaises(ValueError, _int2bytes, -1)
+
+    def test_raises_TypeError_when_not_integer(self):
+        self.assertRaises(TypeError, int2bytes, None)
+        self.assertRaises(TypeError, _int2bytes, None)