change attachments naming strategy from UUID to sha256
remove unused test

remove unused test
add hash generator test

add hash generator test
add attachment save and delete test

add attachment save and delete test
add DirectoryContains matcher

add DirectoryContains matcher
Add ability to remove attachments when test finished
add remove attachment event test

add remove attachment event test
use Guava to hashing

remove lolwaht

rename test method

use type safe matcher

remove unused import

remove utf8 constant

add static imports

remove unused imports