Make ptc exit status 0, 255, or a bitmask of flags for various problems.

t/pt-table-checksum/basics.t

@@ -123,7 +123,7 @@ $exit_status = pt_table_checksum::main(@args,
 
 is(
    $exit_status,
-   1,
+   512,  # = TABLE_DIFF but nothing else; https://bugs.launchpad.net/percona-toolkit/+bug/944051
    "--replicate-check on by default, detects diff"
 );
 
@@ -297,7 +297,7 @@ is_deeply(
 
 is(
    $exit_status,
-   1,
+   2048,
    "Non-zero exit status"
 );
 
@@ -386,8 +386,8 @@ like(
 
 is(
    $exit_status,
-   1,
-   "Exit status 1 when no slaves are found (bug 1087804)"
+   8,  # https://bugs.launchpad.net/percona-toolkit/+bug/944051
+   "Exit status 8 when no slaves are found (bug 1087804)"
 ) or diag($output);
 
 # #############################################################################

t/pt-table-checksum/chunk_index.t

@@ -171,7 +171,7 @@ $output = output(sub {
 
 is(
    $exit_status,
-   0,
+   1024,
    "Bad key_len chunks are not errors"
 ) or diag($output);
 

t/pt-table-checksum/error_handling.t

@@ -153,7 +153,7 @@ like(
 
 is(
    $exit_status,
-   1,
+   2048,  # https://bugs.launchpad.net/percona-toolkit/+bug/944051
    "Non-zero exit status (bug 1009510)"
 );
 

t/pt-table-checksum/standard_options.t

@@ -26,9 +26,6 @@ if ( !$master_dbh ) {
 elsif ( !$slave_dbh ) {
    plan skip_all => 'Cannot connect to sandbox slave1';
 }
-else {
-   plan tests => 6;
-}
 
 # The sandbox servers run with lock_wait_timeout=3 and it's not dynamic
 # so we need to specify --set-vars innodb_lock_wait_timeout=3 else the tool will die.
@@ -116,19 +113,26 @@ like(
 diag(`rm -rf $pid_file >/dev/null 2>&1`);
 diag(`touch $pid_file`);
 
-eval {
-   pt_table_checksum::main(@args, $cnf, '--pid', $pid_file);
-};
+$output = output(
+   sub { $exit_status = pt_table_checksum::main(@args, $cnf, '--pid', $pid_file) },
+   stderr => 1,
+);
 like(
-   $EVAL_ERROR,
-   qr/PID file $pid_file already exists/,
+   $output,
+   qr/PID file $pid_file exists/,
    'Dies if PID file already exists (issue 391)'
 );
 
+is(
+   $exit_status,
+   4,
+   "Exit status 4 if if PID file already exist (bug 944051)"
+);
+
 diag(`rm -rf $pid_file >/dev/null 2>&1`);
 
 # #############################################################################
 # Done.
 # #############################################################################
 ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
-exit;
+done_testing;