Add unit test for svn_io_read_length_line() function.
Add unit test for svn_io_read_length_line() function.

* subversion/tests/libsvn_subr/io-test.c
  (test_read_length_line): New.
  (test_funcs): Add test_read_length_line() to list.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1719066 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion