'Test::Command' intends to bridge the gap between the well tested functions
and objects you choose and their usage in your programs. By examining the
exit status, terminating signal, STDOUT and STDERR of your program you can
determine if it is behaving as expected.

This includes testing the various combinations and permutations of options
and arguments as well as the interactions between the various functions and
objects that make up your program.

The various test functions below can accept either a command string or an
array reference for the first argument. If the command is expressed as a
string it is passed to 'system' as is. If the command is expressed as an
array reference it is dereferenced and passed to 'system' as a list. See
''perldoc -f system'' for how these may differ.

The final argument for the test functions, '$name', is optional. By default
the '$name' is a concatenation of the test function name, the command
string and the expected value. This construction is generally sufficient
for identifying a failing test, but you may always specify your own '$name'
if desired.

Any of the test functions can be used as instance methods on a
'Test::Command' object. This is done by dropping the initial '$cmd'
argument and instead using arrow notation.

All of the following 'exit_is_num' calls are equivalent.

exit_is_num('true', 0);
exit_is_num('true', 0, 'exit_is_num: true, 0');
exit_is_num(['true'], 0);
exit_is_num(['true'], 0, 'exit_is_num: true, 0');

my $cmd = Test::Command->new( cmd => 'true' );

exit_is_num($cmd, 0);
exit_is_num($cmd, 0, 'exit_is_num: true, 0');
$cmd->exit_is_num(0);
$cmd->exit_is_num(0, 'exit_is_num: true, 0');

$cmd = Test::Command->new( cmd => ['true'] );

exit_is_num($cmd, 0);
exit_is_num($cmd, 0, 'exit_is_num: true, 0');
$cmd->exit_is_num(0);
$cmd->exit_is_num(0, 'exit_is_num: true, 0');