break multipart test in two

tests/test_s3/test_s3.py

@@ -39,7 +39,7 @@ def test_my_model_save():
 
 
 @mock_s3
-def test_multipart_upload():
+def test_multipart_upload_too_small():
     conn = boto.connect_s3('the_key', 'the_secret')
     bucket = conn.create_bucket("foobar")
 
@@ -49,12 +49,20 @@ def test_multipart_upload():
     # Multipart with total size under 5MB is refused
     multipart.complete_upload.should.throw(S3ResponseError)
 
+
+@mock_s3
+def test_multipart_upload():
+    conn = boto.connect_s3('the_key', 'the_secret')
+    bucket = conn.create_bucket("foobar")
+
     multipart = bucket.initiate_multipart_upload("the-key")
     part1 = '0' * 5242880
-    multipart.upload_part_from_file(BytesIO('0' * 5242880), 1)
+    multipart.upload_part_from_file(BytesIO(part1), 1)
+    # last part, can be less than 5 MB
     part2 = '1'
-    multipart.upload_part_from_file(BytesIO('1'), 2)
+    multipart.upload_part_from_file(BytesIO(part2), 2)
     multipart.complete_upload()
+    # we should get both parts as the key contents
     bucket.get_key("the-key").get_contents_as_string().should.equal(part1 + part2)