diff --git a/bot/blowfish.py b/bot/blowfish.py
index d0862a9..84feab1 100644
--- a/bot/blowfish.py
+++ b/bot/blowfish.py
@@ -514,8 +514,7 @@ def encrypt(key, plaintext):
 
 def decrypt(key, cyphertext):
     """Decrypt the result of encrypt() using the original key, or raise
-    IncorrectKeyError(). If the cyphertext is malformed, raise
-    BadCyphertextError()."""
+    DecryptionError()."""
     cypher = Blowfish(key)
 
     try:
diff --git a/tests/support.py b/tests/support.py
new file mode 100644
index 0000000..ac65d9d
--- /dev/null
+++ b/tests/support.py
@@ -0,0 +1,21 @@
+# -*- coding: utf-8  -*-
+
+"""
+EarwigBot's Unit Test Support
+
+This module provides some support code for unit tests.
+
+Importing this module will "fix" your path so that EarwigBot code from bot/
+can be imported normally. The run() function runs a given test case.
+"""
+
+from os import path
+import sys
+import unittest
+
+root = path.join(path.split(path.dirname(path.abspath(__file__)))[0], "bot")
+sys.path.insert(0, root)
+
+def run(case):
+    suite = unittest.TestLoader().loadTestsFromTestCase(case)
+    text_runner = unittest.TextTestRunner(verbosity=2).run(suite)
diff --git a/tests/test_blowfish.py b/tests/test_blowfish.py
new file mode 100644
index 0000000..3b209de
--- /dev/null
+++ b/tests/test_blowfish.py
@@ -0,0 +1,77 @@
+# -*- coding: utf-8  -*-
+
+import unittest
+import random
+import string
+
+import support
+import blowfish
+
+class TestBlowfish(unittest.TestCase):
+
+    def test_key_sizes(self):
+        b = blowfish.Blowfish
+        e = blowfish.KeyLengthError
+
+        self.assertRaisesRegexp(e, "no key given", b, None)
+        self.assertRaisesRegexp(e, "no key given", b, "")
+        self.assertRaisesRegexp(e, "at least", b, " " * 3)
+        self.assertRaisesRegexp(e, "at least", b, "1234567")
+        self.assertRaisesRegexp(e, "less than", b, " " * 57)
+        self.assertRaisesRegexp(e, "less than", b, "x" * 60)
+        self.assertRaisesRegexp(e, "less than", b, "1" * 128)
+
+        b("These keys should be valid!")
+        b("'!\"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~'")
+        b(" " * 8)
+        b(" " * 56)
+
+    def test_symmetry(self):
+        def _test_symmetry():
+            key_length = random.randint(8, 56)
+            msg_length = random.randint(0, 4096)
+            key = "".join([random.choice(chars) for i in xrange(key_length)])
+            msg = "".join([random.choice(chars) for i in xrange(msg_length)])
+            
+            enc = blowfish.encrypt(key, msg)
+            dec = blowfish.decrypt(key, enc)
+            self.assertEqual(dec, msg)
+
+        chars = string.letters + string.digits + string.punctuation
+        for i in xrange(8):
+            _test_symmetry()
+
+    def test_encryption(self):
+        tests = [
+            ("example_key", "Hello, I'm a message!", "8411a21574431176cdff9a549d27962c616014a9fe2a1fe3b0c7a823e8a1e635"),
+            ("another random key", "Another random message! :(", "2cdcdf4e53145897ed9d4cc2433aa4bf59b087b14d0ac76a13eff12dec00e60c40857109da3c7bc4"),
+            ("HEY LET'S TRY |°|_J|\|C7|_J/-\\710|\|", "Yes, that was my fail attempt at 1337SP33K >_>", "d4901c7c0956da3b9507cd81cd3c880d7cda25ec6c5336deb9280ce67c099eeddf7c7e052f3a946afbd92c32ae0ab8dbdd875bc5a3f0d686")
+        ]
+
+        for test in tests:
+            self.assertEquals(blowfish.encrypt(test[0], test[1]), test[2])
+
+    def test_decryption(self):
+        tests = [
+            ("blah blah blah", "ab35274c66bb8b3b03c9bd26ab477f3de06857e1d369ad35", "Blah, blah, blah!"),
+            ("random key", "eb2fe950c5c12bca9534ffdd27631f33d3e4bcae53a634b4aaa09f9fe14c4386", "Random message as well!"),
+            ("Okay, now I'm just desperate", "0da74e1cec41e8323da93d0c05bcf3919084130cef93021991da174fd97f8e1c9b125ed5263b41a8", "Unit testing is SO FUN ISN'T IT.")
+        ]
+
+        for test in tests:
+            self.assertEquals(blowfish.decrypt(test[0], test[1]), test[2])
+
+    def test_decryption_exceptions(self):
+        d = blowfish.decrypt
+        e = blowfish.BlowfishError
+
+        e1 = "could not be decoded"
+        e2 = "cannot be broken into 8-byte blocks"
+        e3 = "key is incorrect"
+
+        self.assertRaisesRegexp(e, e1, d, "some_key", "arr!")
+        self.assertRaisesRegexp(e, e2, d, "some_key", "abcd")
+        self.assertRaisesRegexp(e, e3, d, "some_key", "abcdabcdabcdabcd")
+
+if __name__ == "__main__":
+    support.run(TestBlowfish)