From 40db44f2cdd3695e8358a62e88fe7b7732aaee2f Mon Sep 17 00:00:00 2001
From: Mike Fuller <mfuller@atlassian.com>
Date: Mon, 19 Jan 2015 17:03:14 +1100
Subject: [PATCH] Added Exceptions on create_option_group

---
 moto/rds2/exceptions.py      |  1 +
 moto/rds2/models.py          | 18 ++++++++++++++++--
 tests/test_rds2/test_rds2.py | 18 ++++++++++++++++++
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/moto/rds2/exceptions.py b/moto/rds2/exceptions.py
index 936b979d2..a5c935659 100644
--- a/moto/rds2/exceptions.py
+++ b/moto/rds2/exceptions.py
@@ -36,3 +36,4 @@ class DBSubnetGroupNotFoundError(RDSClientError):
         super(DBSubnetGroupNotFoundError, self).__init__(
             'DBSubnetGroupNotFound',
             "Subnet Group {0} not found.".format(subnet_group_name))
+
diff --git a/moto/rds2/models.py b/moto/rds2/models.py
index 67a865c7f..f6edb240b 100644
--- a/moto/rds2/models.py
+++ b/moto/rds2/models.py
@@ -9,7 +9,7 @@ from moto.cloudformation.exceptions import UnformattedGetAttTemplateException
 from moto.core import BaseBackend
 from moto.core.utils import get_random_hex
 from moto.ec2.models import ec2_backends
-from .exceptions import DBInstanceNotFoundError, DBSecurityGroupNotFoundError, DBSubnetGroupNotFoundError
+from .exceptions import RDSClientError, DBInstanceNotFoundError, DBSecurityGroupNotFoundError, DBSubnetGroupNotFoundError
 
 
 class Database(object):
@@ -444,13 +444,27 @@ class RDS2Backend(BaseBackend):
 
     def create_option_group(self, option_group_kwargs):
         option_group_id = option_group_kwargs['name']
+        valid_option_group_engines = {'postgres': ['9.3'], 'mysql': []}
+
+        if 'description' not in option_group_kwargs or not option_group_kwargs['description']:
+            raise RDSClientError('InvalidParameterValue',
+                                 'The parameter OptionGroupDescription must be provided and must not be blank.')
+        if option_group_kwargs['engine_name'] not in valid_option_group_engines.keys():
+            raise RDSClientError('InvalidParameterValue', 'Invalid DB engine: non-existant')
+        if option_group_kwargs['major_engine_version'] not in\
+           valid_option_group_engines[option_group_kwargs['engine_name']]:
+                raise RDSClientError('InvalidParameterCombination',
+                                     'Cannot find major version {0} for {1}'.format(
+                                         option_group_kwargs['major_engine_version'],
+                                         option_group_kwargs['engine_name']
+                                     ))
         option_group = OptionGroup(**option_group_kwargs)
         self.option_groups[option_group_id] = option_group
         return option_group
 
 
 class OptionGroup(object):
-    def __init__(self, name, engine_name, major_engine_version, description):
+    def __init__(self, name, engine_name, major_engine_version, description=None):
         self.engine_name = engine_name
         self.major_engine_version = major_engine_version
         self.description = description
diff --git a/tests/test_rds2/test_rds2.py b/tests/test_rds2/test_rds2.py
index dd44719e4..d75f294f3 100644
--- a/tests/test_rds2/test_rds2.py
+++ b/tests/test_rds2/test_rds2.py
@@ -73,6 +73,24 @@ def test_create_option_group():
     option_group['CreateOptionGroupResponse']['CreateOptionGroupResult']['OptionGroup']['OptionGroupDescription'].should.equal('test option group')
     option_group['CreateOptionGroupResponse']['CreateOptionGroupResult']['OptionGroup']['MajorEngineVersion'].should.equal('9.3')
 
+@mock_rds2
+def test_create_option_group_bad_engine_name():
+    conn = boto.rds2.connect_to_region("us-west-2")
+    conn.create_option_group.when.called_with('test', 'invalid_engine', '9.3', 'test invalid engine').should.throw(BotoServerError)
+
+
+@mock_rds2
+def test_create_option_group_bad_engine_major_version():
+    conn = boto.rds2.connect_to_region("us-west-2")
+    conn.create_option_group.when.called_with('test', 'postgres', '9.3.a', 'test invalid engine version').should.throw(BotoServerError)
+
+
+@mock_rds2
+def test_create_option_group_empty_description():
+    conn = boto.rds2.connect_to_region("us-west-2")
+    conn.create_option_group.when.called_with('test', 'postgres', '9.3', '').should.throw(BotoServerError)
+
+
 #@disable_on_py3()
 #@mock_rds2
 #def test_delete_database():