S3 Mock should return an HTTP 409 if trying to create a bucket that

already exists. Closes #94.

moto/s3/exceptions.py

@@ -0,0 +1,2 @@
+class BucketAlreadyExists(Exception):
+    pass

moto/s3/models.py

@@ -5,10 +5,11 @@ import hashlib
 
 from moto.core import BaseBackend
 from moto.core.utils import iso_8601_datetime, rfc_1123_datetime
+from .exceptions import BucketAlreadyExists
 from .utils import clean_key_name
 
-UPLOAD_ID_BYTES=43
-UPLOAD_PART_MIN_SIZE=5242880
+UPLOAD_ID_BYTES = 43
+UPLOAD_PART_MIN_SIZE = 5242880
 
 
 class FakeKey(object):
@@ -107,6 +108,8 @@ class S3Backend(BaseBackend):
         self.buckets = {}
 
     def create_bucket(self, bucket_name):
+        if bucket_name in self.buckets:
+            raise BucketAlreadyExists()
         new_bucket = FakeBucket(name=bucket_name)
         self.buckets[bucket_name] = new_bucket
         return new_bucket

moto/s3/responses.py

@@ -3,6 +3,7 @@ import re
 
 from jinja2 import Template
 
+from .exceptions import BucketAlreadyExists
 from .models import s3_backend
 from .utils import bucket_name_from_url
 
@@ -66,7 +67,10 @@ class ResponseObject(object):
             else:
                 return 404, headers, ""
         elif method == 'PUT':
-            new_bucket = self.backend.create_bucket(bucket_name)
+            try:
+                new_bucket = self.backend.create_bucket(bucket_name)
+            except BucketAlreadyExists:
+                return 409, headers, ""
             template = Template(S3_BUCKET_CREATE_RESPONSE)
             return template.render(bucket=new_bucket)
         elif method == 'DELETE':
@@ -148,7 +152,7 @@ class ResponseObject(object):
                     upload_id=upload_id,
                     count=len(parts),
                     parts=parts
-                    )
+                )
             key = self.backend.get_key(bucket_name, key_name)
             if key:
                 headers.update(key.metadata)