Corrections to system probe

[plicease]

At least for the astyle provided for my Debian Linux, the version number is printed to stderr, not stdout. Also, checking $? is a reliable way for catching things like "command not found".

[plicease]

The binary built from source appears to print to stderr. So you probably actually want to check both stdout and stderr. Both here and in the t/03_binary_version.t. So this PR isn't exactly right, but hopefully it gives you the idea.

[plicease]

Here is the test failure that I see after applying this patch:

iscah% prove -bv 
t/01_use.t ................ 
1..1
ok 1 - use Alien::astyle;
ok
t/02_binary_executable.t .. 
1..10
ok 1 - use Alien::astyle;
not ok 2 - Alien::astyle->bin_dir() is defined

#   Failed test 'Alien::astyle->bin_dir() is defined'
#   at t/02_binary_executable.t line 11.
ok 3 - Alien::astyle->bin_dir() is not empty
not ok 4 - Alien::astyle->bin_dir() exists
Use of uninitialized value $astyle_bin_dir in -e at t/02_binary_executable.t line 13.

#   Failed test 'Alien::astyle->bin_dir() exists'
#   at t/02_binary_executable.t line 13.
Use of uninitialized value $astyle_bin_dir in -r at t/02_binary_executable.t line 14.
not ok 5 - Alien::astyle->bin_dir() is readable

#   Failed test 'Alien::astyle->bin_dir() is readable'
#   at t/02_binary_executable.t line 14.
Use of uninitialized value $astyle_bin_dir in -d at t/02_binary_executable.t line 15.
not ok 6 - Alien::astyle->bin_dir() is a directory

#   Failed test 'Alien::astyle->bin_dir() is a directory'
#   at t/02_binary_executable.t line 15.
Use of uninitialized value in subroutine entry at t/02_binary_executable.t line 17.
not ok 7 - astyle exists

#   Failed test 'astyle exists'
#   at t/02_binary_executable.t line 18.
not ok 8 - astyle is readable

#   Failed test 'astyle is readable'
#   at t/02_binary_executable.t line 19.
not ok 9 - astyle is a file

#   Failed test 'astyle is a file'
#   at t/02_binary_executable.t line 20.
not ok 10 - astyle is executable

#   Failed test 'astyle is executable'
#   at t/02_binary_executable.t line 21.
# Looks like you failed 8 tests of 10.
Dubious, test returned 8 (wstat 2048, 0x800)
Failed 8/10 subtests 
t/03_binary_version.t ..... 
1..7
ok 1 - use Alien::astyle;
Use of uninitialized value in subroutine entry at t/03_binary_version.t line 12.
not ok 2 - `astyle --version` executes without displaying errors

#   Failed test '`astyle --version` executes without displaying errors'
#   at t/03_binary_version.t line 18.
#          got: 'Can't exec "/astyle": No such file or directory at t/03_binary_version.t line 16.
# '
#     expected: ''
not ok 3 - `astyle --version` executes with 1 line of output

#   Failed test '`astyle --version` executes with 1 line of output'
#   at t/03_binary_version.t line 19.
#          got: 0
#     expected: 1
not ok 4 - `astyle --version` 1 line of output is defined

#   Failed test '`astyle --version` 1 line of output is defined'
#   at t/03_binary_version.t line 22.
Use of uninitialized value within @_ in list assignment at /home/ollisg/.perlbrew/libs/perl-5.25.3tc@dev/lib/perl5/Test/Builder.pm line 730.
not ok 5 - `astyle --version` 1 line of output starts correctly

#   Failed test '`astyle --version` 1 line of output starts correctly'
#   at t/03_binary_version.t line 23.
#          got: ''
#     expected: 'Artistic Style Version'
Use of uninitialized value $version_stdout_0 in pattern match (m//) at t/03_binary_version.t line 24.
not ok 6 - `astyle --version` 1 line of output ends correctly

#   Failed test '`astyle --version` 1 line of output ends correctly'
#   at t/03_binary_version.t line 24.
Use of uninitialized value $1 in split at t/03_binary_version.t line 26.
Use of uninitialized value in addition (+) at t/03_binary_version.t line 27.
not ok 7 - `astyle --version` returns major version 2 or newer

#   Failed test '`astyle --version` returns major version 2 or newer'
#   at t/03_binary_version.t line 28.
#          got: 0
#     expected: 2
# Looks like you failed 6 tests of 7.
Dubious, test returned 6 (wstat 1536, 0x600)
Failed 6/7 subtests 

Test Summary Report
-------------------
t/02_binary_executable.t (Wstat: 2048 Tests: 10 Failed: 8)
  Failed tests:  2, 4-10
  Non-zero exit status: 8
t/03_binary_version.t   (Wstat: 1536 Tests: 7 Failed: 6)
  Failed tests:  2-7
  Non-zero exit status: 6
Files=3, Tests=18,  0 wallclock secs ( 0.04 usr  0.00 sys +  0.18 cusr  0.01 csys =  0.23 CPU)
Result: FAIL

the first test fails because Alien::astyle->bin_dir returns empty list in a system install since astyle is already in the PATH. The second fails because the Debian version prints the version to stderr. I suspect that this is because the Debian version is older.