diff --git a/tests/scripts/tcp_client.pl b/tests/scripts/tcp_client.pl
new file mode 100755
index 0000000..11cbf1b
--- /dev/null
+++ b/tests/scripts/tcp_client.pl
@@ -0,0 +1,86 @@
+#!/usr/bin/env perl
+
+# A simple TCP client that sends some data and expects a response.
+# Usage: tcp_client.pl HOSTNAME PORT DATA1 RESPONSE1
+#   DATA: hex-encoded data to send to the server
+#   RESPONSE: regexp that must match the server's response
+
+use warnings;
+use strict;
+use IO::Socket::INET;
+
+# Pack hex digits into a binary string, ignoring whitespace.
+sub parse_hex {
+    my ($hex) = @_;
+    $hex =~ s/\s+//g;
+    return pack('H*', $hex);
+}
+
+## Open a TCP connection to the specified host and port.
+sub open_connection {
+    my ($host, $port) = @_;
+    my $socket = IO::Socket::INET->new(PeerAddr => $host,
+                                       PeerPort => $port,
+                                       Proto => 'tcp',
+                                       Timeout => 1);
+    die "Cannot connect to $host:$port: $!" unless $socket;
+    return $socket;
+}
+
+## Close the TCP connection.
+sub close_connection {
+    my ($connection) = @_;
+    $connection->shutdown(2);
+    # Ignore shutdown failures (at least for now)
+    return 1;
+}
+
+## Write the given data, expressed as hexadecimal
+sub write_data {
+    my ($connection, $hexdata) = @_;
+    my $data = parse_hex($hexdata);
+    my $total_sent = 0;
+    while ($total_sent < length($data)) {
+        my $sent = $connection->send($data, 0);
+        if (!defined $sent) {
+            die "Unable to send data: $!";
+        }
+        $total_sent += $sent;
+    }
+    return 1;
+}
+
+## Read a response and check it against an expected prefix
+sub read_response {
+    my ($connection, $expected_hex) = @_;
+    my $expected_data = parse_hex($expected_hex);
+    my $start_offset = 0;
+    while ($start_offset < length($expected_data)) {
+        my $actual_data;
+        my $ok = $connection->recv($actual_data, length($expected_data));
+        if (!defined $ok) {
+            die "Unable to receive data: $!";
+        }
+        if (($actual_data ^ substr($expected_data, $start_offset)) =~ /[^\000]/) {
+            printf STDERR ("Received \\x%02x instead of \\x%02x at offset %d\n",
+                           ord(substr($actual_data, $-[0], 1)),
+                           ord(substr($expected_data, $start_offset + $-[0], 1)),
+                           $start_offset + $-[0]);
+            return 0;
+        }
+        $start_offset += length($actual_data);
+    }
+    return 1;
+}
+
+if (@ARGV != 4) {
+    print STDERR "Usage: $0 HOSTNAME PORT DATA1 RESPONSE1\n";
+    exit(3);
+}
+my ($host, $port, $data1, $response1) = @ARGV;
+my $connection = open_connection($host, $port);
+write_data($connection, $data1);
+if (!read_response($connection, $response1)) {
+    exit(1);
+}
+close_connection($connection);