/**
@page run_test_howto How to write a run_test.pl

ACE/TAO's auto_builds expect run_test.pl's to follow some guidelines
that are needed to keep the auto_builds from hanging and to make
sure the run_test.pl works on all platforms

- The run_test must not hang or block.
- The run_test must clean up any temporary files when it is done.
- The run_test must not require any user input
- The run_test should return a non-zero value if the test failed
- When an executable can't be spawned the test should directly exit and
  not wait for a fail to be created by that executable
- The processes should support that files names are passed through
  the commandline

Following is an example

@subsection example Example

@verbatim
eval '(exit $?0)' && eval 'exec perl -S $0 ${1+"$@"}'
    & eval 'exec perl -S $0 $argv:q'
    if 0;

# -*- perl -*-

use lib "$ENV{ACE_ROOT}/bin";
use PerlACE::TestTarget;

$status = 0;

my $server = PerlACE::TestTarget::create_target (1) || die "Create target 1 failed\n";
my $client = PerlACE::TestTarget::create_target (2) || die "Create target 2 failed\n";

$plain_server_ior = "server.ior";
my $iorbase = "server.ior";
my $server_iorfile = $server->LocalFile ($iorbase);
my $client_iorfile = $client->LocalFile ($iorbase);
$server->DeleteFile($iorbase);
$client->DeleteFile($iorbase);

$SV = $server->CreateProcess ("server", "-ORBdebuglevel $debug_level -o $server_iorfile");
$CL = $client->CreateProcess ("client", "-k file://$client_iorfile");

$server_status = $SV->Spawn ();

if ($server_status != 0) {
    print STDERR "ERROR: server returned $server_status\n";
    exit 1;
}

if ($server->WaitForFileTimed ($iorbase,
                               $server->ProcessStartWaitInterval()) == -1) {
    print STDERR "ERROR: cannot find file <$server_iorfile>\n";
    $SV->Kill (); $SV->TimedWait (1);
    exit 1;
}

if ($server->GetFile ($iorbase) == -1) {
    print STDERR "ERROR: cannot retrieve file <$server_iorfile>\n";
    $SV->Kill (); $SV->TimedWait (1);
    exit 1;
}
if ($client->PutFile ($iorbase) == -1) {
    print STDERR "ERROR: cannot set file <$client_iorfile>\n";
    $SV->Kill (); $SV->TimedWait (1);
    exit 1;
}

$client_status = $CL->SpawnWaitKill ($client->ProcessStartWaitInterval());

if ($client_status != 0) {
    print STDERR "ERROR: client returned $client_status\n";
    $status = 1;
}

$server_status = $SV->WaitKill ($server->ProcessStopWaitInterval());

if ($server_status != 0) {
    print STDERR "ERROR: server returned $server_status\n";
    $status = 1;
}

$server->GetStderrLog();
$client->GetStderrLog();

$server->DeleteFile($server_iorfile);
$client->DeleteFile($client_iorfile);

exit $status;

@endverbatim

@subsection details Example Details

@verbatim
eval '(exit $?0)' && eval 'exec perl -S $0 ${1+"$@"}'
    & eval 'exec perl -S $0 $argv:q'
    if 0;

@endverbatim

This is the standard header stuff.  The eval is a trick used
to get the perl script to run if it a unix shell treats it as
a shell script.

The SVN ID string is the usual one we put in.

@verbatim
use lib "$ENV{ACE_ROOT}/bin";
use PerlACE::TestTarget;
@endverbatim

The use lib line is used to tell Perl where the PerlACE modules are.
It should NOT be a relative path to the bin directory.  This is how
it used to be done, but doing so would be incompatible with the "flat"
directory layout of ACE+TAO.  The correct way is demonstrated above.
After the "use lib" line, always use $PerlACE::TAO_ROOT to reference
the location of TAO.  Use either $ENV{ACE_ROOT} or $PerlACE::ACE_ROOT
to reference the location of ACE.

And PerlACE::Run_Test is a module to be used by all run_test.pl's.
It does a couple of things, including parsing some common command
line arguments (like -Config and -ExeSubDir) and also brings in
the PerlACE::Process module.

@verbatim
my $server = PerlACE::TestTarget::create_target (1) || die "Create target 1 failed\n";
my $client = PerlACE::TestTarget::create_target (2) || die "Create target 2 failed\n";
@endverbatim

We need to have two targets to run the tst on

@verbatim
my $iorbase = "server.ior";
my $server_iorfile = $server->LocalFile ($iorbase);
my $client_iorfile = $client->LocalFile ($iorbase);
$server->DeleteFile($iorbase);
$client->DeleteFile($iorbase);
@endverbatim

We need to have a fully
qualified path to all *.ior and *.conf files.  We unlink the file
immediately because we use WaitForFileTimed later.

@verbatim
$SV = $server->CreateProcess ("server", "-ORBdebuglevel $debug_level -o $server_iorfile");
@endverbatim

The server we have to spawn

@verbatim
$CL = $client->CreateProcess ("client", "-k file://$client_iorfile");

$server_status = $SV->Spawn ();

if ($server_status != 0) {
    print STDERR "ERROR: server returned $server_status\n";
    exit 1;
}
@endverbatim

The PerlACE::Process is created with an executable and
arguments.  @note Unlike the old Process module, the process
isn't started until one of the Spawn methods is used. We check
the result of the spawn, if we couldn't spawn the process
we directly exit the script.

@verbatim
if ($server->WaitForFileTimed ($iorbase,
                               $server->ProcessStartWaitInterval()) == -1) {
    print STDERR "ERROR: cannot find file <$server_iorfile>\n";
    $SV->Kill (); $SV->TimedWait (1);
    exit 1;
}
@endverbatim

The WaitForFileTimed method waits until the file is
created.  In this way, we know when to start the client.  If
no IOR file is used, then you'd need to use Perl's sleep
method.

@verbatim
if ($server->GetFile ($iorbase) == -1) {
    print STDERR "ERROR: cannot retrieve file <$server_iorfile>\n";
    $SV->Kill (); $SV->TimedWait (1);
    exit 1;
}
if ($client->PutFile ($iorbase) == -1) {
    print STDERR "ERROR: cannot set file <$client_iorfile>\n";
    $SV->Kill (); $SV->TimedWait (1);
    exit 1;
}
@endverbatim

This transfers the file from the server to the client in
case that is needed with the used test targets.

@verbatim
$client_status = $CL->SpawnWaitKill ($client->ProcessStartWaitInterval());

if ($client_status != 0) {
    print STDERR "ERROR: client returned $client_status\n";
    $status = 1;
}
@endverbatim

Here is an example of starting the client.  SpawnWaitKill will start
the process and wait for the specified number of seconds for the
process to end.  If the time limit is reached, it will kill the
process and return -1.

The return value of SpawnWaitKill is the return value of the
process, unless it timed out.  You don't need to check for the
timeout, since SpawnWaitKill will print out a timeout error.
Instead, just check for != 0.

@verbatim
$server_status = $SV->WaitKill ($server->ProcessStopWaitInterval());

if ($server_status != 0) {
    print STDERR "ERROR: server returned $server_status\n";
    $status = 1;
}
@endverbatim

Here is the termination of the server.  Servers are usually terminated
either by TerminateWaitKill or just WaitKill.  TerminateWaitKill is
used when the server doesn't shut down itself.  WaitKill is used when
it does (such as when the client calls a shutdown method).  Once
again, we check the return status.

@verbatim
$server->GetStderrLog();
$client->GetStderrLog();

$server->DeleteFile($server_iorfile);
$client->DeleteFile($client_iorfile);

exit $status;
@endverbatim

This example illustrates how to get the host name within the cross
platform test. In your test program add functionality to handle a
command line argument to pass the host name of the target. In the
run_test.pl script you can use the following code as example.

@verbatim
my $server = PerlACE::TestTarget::create_target (1) || die "Create target 1 failed\n";
my $hostname = $server->HostName();
$SV = $server->CreateProcess ("server", "-ORBEndpoint iiop://$hostname:43210");
$CL = $server->CreateProcess ("client", " -p 43210 -h $hostname");
@endverbatim

And finally, we unlink any files that were created and then just
exit with $status.

*/
