diff --git a/t/pt-query-digest/bugs.t b/t/pt-query-digest/bugs.t
new file mode 100644
index 00000000..ab025cfd
--- /dev/null
+++ b/t/pt-query-digest/bugs.t
@@ -0,0 +1,57 @@
+#!/usr/bin/env perl
+
+BEGIN {
+   die "The PERCONA_TOOLKIT_BRANCH environment variable is not set.\n"
+      unless $ENV{PERCONA_TOOLKIT_BRANCH} && -d $ENV{PERCONA_TOOLKIT_BRANCH};
+   unshift @INC, "$ENV{PERCONA_TOOLKIT_BRANCH}/lib";
+};
+
+use strict;
+use warnings FATAL => 'all';
+use English qw(-no_match_vars);
+use Test::More;
+
+use Sandbox;
+use PerconaTest;
+# See 101_slowlog_analyses.t for why we shift.
+shift @INC;  # our unshift (above)
+shift @INC;  # PerconaTest's unshift
+shift @INC;  # Sandbox
+
+require "$trunk/bin/pt-query-digest";
+
+my $dp  = new DSNParser(opts=>$dsn_opts);
+my $sb  = new Sandbox(basedir => '/tmp', DSNParser => $dp);
+my $dbh = $sb->get_dbh_for('master');
+
+if ( !$dbh ) {
+   plan skip_all => 'Cannot connect to sandbox master';
+}
+
+my $output  = '';
+my $exit_status;
+my $cnf     = 'h=127.1,P=12345,u=msandbox,p=msandbox';
+my $samples = "$trunk/t/pt-query-digest/samples";
+
+# #############################################################################
+# pt-query-digest with custom --group-by throws error
+# https://bugs.launchpad.net/percona-toolkit/+bug/957442
+# #############################################################################
+
+$output = output(sub {
+   $exit_status = pt_query_digest::main('--group-by=page',
+         '--filter', "$samples/bug_957442_filter.pl",
+         "$samples/bug_957442_sample.log")
+});
+
+ok(
+   !$exit_status,
+   "Bug 957442: No error with a custom --filter & --group-by=page"
+);
+
+# #############################################################################
+# Done.
+# #############################################################################
+$sb->wipe_clean($dbh);
+ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
+done_testing;
diff --git a/t/pt-query-digest/samples/bug_957442_filter.pl b/t/pt-query-digest/samples/bug_957442_filter.pl
new file mode 100644
index 00000000..72152139
--- /dev/null
+++ b/t/pt-query-digest/samples/bug_957442_filter.pl
@@ -0,0 +1,9 @@
+use strict;
+use warnings FATAL => 'all';
+use Data::Dumper;
+my $page = 0;
+if ( $event->{arg} ) {
+   ($page) = $event->{arg} =~ m#/\*page_(\d+)\*/#g;
+}
+$event->{page} = ($page || 0);
+1
diff --git a/t/pt-query-digest/samples/bug_957442_sample.log b/t/pt-query-digest/samples/bug_957442_sample.log
new file mode 100644
index 00000000..c4da45c0
--- /dev/null
+++ b/t/pt-query-digest/samples/bug_957442_sample.log
@@ -0,0 +1,58 @@
+# Time: 120315 18:01:58.479076
+# User@Host: EpiFou2[EpiFou2] @ 10.42.1.136 []
+# Client: 10.42.1.136:52714
+# Thread_id: 1989712101
+# Query_time: 0.001084  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0
+use faidr3;
+# administrator command: Connect;
+# Time: 120315 18:01:58.480646
+# User@Host: EpiFou2[EpiFou2] @ 10.60.24.110 []
+# Client: 10.60.24.110:59474
+# Thread_id: 1989712100
+# Query_time: 0.002040  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0
+use faidr3;
+SELECT id, meta, faidelog_id
+                        FROM   posts_ref
+                        /*page_3*/ 
+                        ORDER BY id DESC LIMIT 11;
+# Time: 120315 18:01:58.481714
+# User@Host: EpiFou2[EpiFou2] @ 10.60.24.110 []
+# Client: 10.60.24.110:59474
+# Thread_id: 1989712100
+# Query_time: 0.000000  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0
+use faidr3;
+# administrator command: Quit;
+# Time: 120315 18:01:58.482088
+# User@Host: EpiFou2[EpiFou2] @ 10.42.1.136 []
+# Client: 10.42.1.136:52714
+# Thread_id: 1989712101
+# Query_time: 0.002632  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0
+use faidr3;
+SELECT SQL_CALC_FOUND_ROWS id, faidelog_id
+                        FROM   posts_ref
+                        WHERE  NOT (meta & 0x00000008) AND faidelog_id = 16067957 /*page_8*/ 
+                        ORDER BY meta DESC, id DESC LIMIT 105, 15;
+# Time: 120315 18:01:58.482571
+# User@Host: EpiFou2[EpiFou2] @ 10.42.1.136 []
+# Client: 10.42.1.136:52714
+# Thread_id: 1989712101
+# Query_time: 0.000000  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0
+use faidr3;
+# administrator command: Quit;
+# Time: 120315 18:01:58.497459
+# User@Host: EpiFou2[EpiFou2] @ 10.60.24.96 []
+# Client: 10.60.24.96:35130
+# Thread_id: 1989712113
+# Query_time: 0.000483  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0
+use faidr3;
+# administrator command: Connect;
+# Time: 120315 18:01:58.501509
+# User@Host: EpiFou2[EpiFou2] @ 10.60.24.96 []
+# Client: 10.60.24.96:35130
+# Thread_id: 1989712113
+# Query_time: 0.003460  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0
+use faidr3;
+SELECT id, meta, faidelog_id
+                        FROM   posts_ref
+                        /*page_2*/ 
+                        ORDER BY id DESC LIMIT 11;