diff --git a/t/40_tls13.only.t b/t/40_tls13.only.t
new file mode 100755
index 0000000..8a76ea5
--- /dev/null
+++ b/t/40_tls13.only.t
@@ -0,0 +1,101 @@
+#!/usr/bin/env perl
+
+# As the name indicates: Check for TLS 1.3 only hosts
+
+use strict;
+use warnings;
+use Test::More;
+use IPC::Run qw( start timeout );
+use File::Temp qw( tempdir );
+use File::Basename;
+use File::Path qw( remove_tree );
+use File::Copy;
+
+my $port = 1443;
+my $server_script;
+my $temp_dir;
+
+BEGIN {
+    $temp_dir = tempdir(CLEANUP => 1);
+    # Path to the testssl.sh script (assuming we are in the project root)
+    $server_script = "$temp_dir/start_server.sh";
+}
+
+# 2. The Shell Script (HEREDOC)
+# We adapt your snippet slightly to ensure it runs deterministically as a test.
+my $shell_code = <<'HEREDOC';
+#!/bin/bash
+# Configuration
+PORT=1443
+CERT="server.pem"
+KEY="server.key"
+PROTOCOL="tls1_3"
+DAYS=365
+OPENSSL=/usr/bin/openssl
+
+# For a test, we force a specific TLS 1.3 cipher suite to ensure the server starts reliably
+# instead of relying on defaults or user input.
+# CIPHER_SUITE="TLS_AES_256_GCM_SHA384"
+
+# Generate self-signed cert and key if they don't exist
+if [ ! -f "$CERT" ] || [ ! -f "$KEY" ]; then
+    echo "Generating self-signed certificate and key..."
+    $OPENSSL req -x509 -newkey rsa:2048 -keyout "$KEY" -out "$CERT" -days "$DAYS" -nodes -subj "/CN=localhost"
+fi
+
+# Start OpenSSL server
+# Note: We use -tls1_3 to enable TLS 1.3.
+echo "Starting server on port $PORT..."
+# $OPENSSL s_server -accept "$PORT" -cert "$CERT" -key "$KEY" -tls1_3 -ciphersuites "$CIPHER_SUITE"
+$OPENSSL s_server -accept "$PORT" -cert "$CERT" -key "$KEY" -tls1_3
+HEREDOC
+
+# 3. Setup: Write and execute the script
+subtest 'TLS 1.3 Only Server Setup', sub {
+    plan skip_all => "IPC::Run not available" unless eval { require IPC::Run; 1 };
+
+    # Write the script to the temp directory
+    open(my $fh, '>', $server_script) or die "Cannot write script: $!";
+    print $fh $shell_code;
+    close($fh);
+
+    chmod 0755, $server_script;
+
+    # Start the server in the background
+    my $server = IPC::Run::start([ $server_script ]);
+
+    # Wait for the server to be listening on the port
+    my $ready = 0;
+    for my $i (1..20) {
+        if (system("nc -z localhost $port") == 0) {
+            $ready = 1;
+            last;
+        }
+        sleep 1;
+    }
+
+    ok($ready, "Server is listening on port $port");
+
+    if (!$ready) {
+        diag("Server failed to start");
+        $server->finish;
+        return;
+    }
+
+    # Run testssl.sh
+    my $testssl_output = `./testssl.sh --protocols localhost:$port 2>&1`;
+
+    # Verify
+    like($testssl_output, qr/TLS 1\.3/, "TLS 1.3 is supported");
+
+    # Check if TLS 1.2 is NOT found (since we only enabled tls1_3)
+    # We look for "TLS 1.2" but try to exclude it if it's in a "not supported" section, 
+    # but usually testssl prints "NOT offered" or similar.
+    # A safer check for "TLS 1.3 ONLY" is to ensure 1.2 is explicitly rejected.
+    unlike($testssl_output, qr/OFFERED\s+TLS 1\.2/, "TLS 1.2 is NOT offered");
+
+    # Cleanup the server process
+    $server->finish;
+};
+
+done_testing();