Creating a database that already exists in the glue data catalog raises an exception

tests/test_glue/test_datacatalog.py

@@ -1,7 +1,9 @@
 from __future__ import unicode_literals
 
 import sure  # noqa
+from nose.tools import assert_raises
 import boto3
+from botocore.client import ClientError
 
 from moto import mock_glue
 
@@ -28,3 +30,15 @@ def test_create_database():
     database = response['Database']
 
     database.should.equal({'Name': database_name})
+
+
+@mock_glue
+def test_create_database_already_exists():
+    client = boto3.client('glue', region_name='us-east-1')
+    database_name = 'anewdatabase'
+    create_database(client, database_name)
+
+    with assert_raises(ClientError) as exc:
+        create_database(client, database_name)
+
+    exc.exception.response['Error']['Code'].should.equal('DatabaseAlreadyExistsException')