bnot ok 1
#     Failed test (diamond.pl at line 35)
#          got: 'a'
#     expected: 'b'
Undefined subroutine &main::write_and_read_file called at diamond.pl line 15, <> line 1.
1..1
# Looks like you failed 1 tests of 1.
# Looks like your test died just after 1.