tests that a closedchannelexception is thrown when trying to append to a channel afterclosing it . concode_field_sep LocalFileBlockWriter mWriter concode_elem_sep ExpectedException mThrown concode_elem_sep TemporaryFolder mFolder concode_elem_sep long TEST_BLOCK_SIZE concode_elem_sep String mTestFilePath concode_field_sep void before concode_elem_sep void getChannel concode_elem_sep void append