--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/comm.rs	Fri Nov 27 10:07:35 2020 +0100
@@ -0,0 +1,57 @@
+use std::process::Child;
+use std::ffi::OsStr;
+use std::io::{self, Read, Write};
+
+pub trait Test {
+    const SOCKET_ADDR: &'static str;
+
+    fn spawn_slave(program_name: &OsStr) -> io::Result<Child>;
+}
+
+const REQUEST: &[u8] = b"orange coin";
+const RESPONSE: &[u8] = b"good";
+
+fn main_master(slave: io::Result<Child>) {
+    let mut slave = slave.expect("failed to run systemd-socket-activate");
+
+    // give slave some time to bind the socket just to be sure
+    std::thread::sleep(std::time::Duration::from_secs(1));
+
+    let mut client_socket = std::net::TcpStream::connect("127.0.0.1:4242").expect("Failed to connect to 127.0.0.1:4242");
+    client_socket.write_all(REQUEST).expect("failed to send data");
+    let mut buf = [0u8; RESPONSE.len()];
+    client_socket.read_exact(&mut buf).expect("failed to read response");
+    assert_eq!(buf, RESPONSE);
+
+    let status = slave.wait().expect("faild to wait for slave");
+    if !status.success() {
+        panic!("slave did not exit with succcess, status: {}", status);
+    }
+}
+
+fn main_slave(addr: &str) {
+    use systemd_socket::SocketAddr;
+
+    let socket = addr
+        .parse::<SocketAddr>()
+        .expect("failed to parse socket")
+        .bind()
+        .expect("failed to bind");
+
+    let (mut client_socket, _) = socket.accept().expect("failed to accept");
+    let mut buf = [0u8; REQUEST.len()];
+    client_socket.read_exact(&mut buf).expect("failed to read response");
+    assert_eq!(buf, REQUEST);
+    client_socket.write_all(RESPONSE).expect("failed to send data");
+}
+
+pub fn main<T: Test>() {
+    let mut args = std::env::args_os();
+    let program_name = args.next().expect("missing program name");
+
+    match std::env::var_os("SYSTEMD_SOCKET_INTEGRATION_TEST") {
+        None => main_master(T::spawn_slave(&program_name)),
+        Some(arg) if arg == "slave" => main_slave(T::SOCKET_ADDR),
+        Some(arg) => panic!("Unknown argument '{:?}'", arg),
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/ordinary.rs	Fri Nov 27 10:07:35 2020 +0100
@@ -0,0 +1,22 @@
+use std::io;
+use std::ffi::OsStr;
+use std::process::{Command, Child};
+
+mod comm;
+
+enum Test {}
+
+impl comm::Test for Test {
+    const SOCKET_ADDR: &'static str = "127.0.0.1:4242";
+
+    fn spawn_slave(program_name: &OsStr) -> io::Result<Child> {
+        Command::new(program_name)
+            .env("SYSTEMD_SOCKET_INTEGRATION_TEST", "slave")
+            .spawn()
+    }
+}
+
+#[test]
+fn main() {
+    comm::main::<Test>();
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/systemd.rs	Fri Nov 27 10:07:35 2020 +0100
@@ -0,0 +1,28 @@
+// This integration test requires presence of systemd-socket-activate
+
+use std::io;
+use std::ffi::OsStr;
+use std::process::{Command, Child};
+
+mod comm;
+
+enum Test {}
+
+impl comm::Test for Test {
+    const SOCKET_ADDR: &'static str = "systemd://secret_socket_of_satoshi_nakamoto";
+
+    fn spawn_slave(program_name: &OsStr) -> io::Result<Child> {
+        Command::new("systemd-socket-activate")
+            .arg("-l")
+            .arg("127.0.0.1:4242")
+            .arg("--fdname=secret_socket_of_satoshi_nakamoto")
+            .arg("--setenv=SYSTEMD_SOCKET_INTEGRATION_TEST=slave")
+            .arg(program_name)
+            .spawn()
+    }
+}
+
+#[test]
+fn main() {
+    comm::main::<Test>();
+}