* rename unit test

Author: HYLcool

tests/buffer/file_test.py

@@ -16,7 +16,7 @@
 from trinity.common.constants import StorageType
 
 
-class TestFileReader(unittest.TestCase):
+class TestFileBuffer(unittest.TestCase):
     temp_output_path = "tmp/test_file_buffer/"
 
     @classmethod