Implementing KMS encrypt/decrypt

This adds support for testing the /encrypt and /decrypt endpoints
of Amazon KMS

tests/test_kms/test_kms.py

@@ -1,5 +1,6 @@
 from __future__ import unicode_literals
 import re
+import six
 
 import boto.kms
 from boto.exception import JSONResponseError
@@ -136,6 +137,27 @@ def test_disable_key_rotation():
     conn.get_key_rotation_status(key_id)['KeyRotationEnabled'].should.equal(False)
 
 
+# Scoping encryption/decryption to only Python 2 because our test suite
+# hardcodes a dependency on boto version 2.36.0 which is not compatible with
+# Python 3 (2.40+, however, passes these tests).
+if six.PY2:
+    @mock_kms
+    def test_encrypt():
+        """
+        Using base64 encoding to merely test that the endpoint was called
+        """
+        conn = boto.kms.connect_to_region("us-west-2")
+        response = conn.encrypt('key_id', 'encryptme'.encode('utf-8'))
+        response['CiphertextBlob'].should.equal('ZW5jcnlwdG1l')
+
+
+    @mock_kms
+    def test_decrypt():
+        conn = boto.kms.connect_to_region('us-west-2')
+        response = conn.decrypt('ZW5jcnlwdG1l'.encode('utf-8'))
+        response['Plaintext'].should.equal('encryptme')
+
+
 @mock_kms
 def test_disable_key_rotation_with_missing_key():
     conn = boto.kms.connect_to_region("us-west-2")