Add integration test (#383)

* Add integration test

Fixes #382

* Skip integration test where not appropriate

src/bin/spawn_client_test_helper.rs

@@ -0,0 +1,24 @@
+// Copyright 2025 The Servo Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use ipc_channel::ipc::IpcSender;
+use std::{env, process};
+
+/// Test executable which connects to the one-shot server with name
+/// passed in as an argument and then sends a test message to the
+/// server.
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    let token = args.get(1).expect("missing argument");
+
+    let tx: IpcSender<String> = IpcSender::connect(token.to_string()).expect("connect failed");
+    tx.send("test message".to_string()).expect("send failed");
+
+    process::exit(0);
+}

tests/integration_test.rs

@@ -0,0 +1,44 @@
+// Copyright 2025 The Servo Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[cfg(not(any(feature = "force-inprocess", target_os = "android", target_os = "ios")))]
+use ipc_channel::ipc::IpcOneShotServer;
+#[cfg(not(any(feature = "force-inprocess", target_os = "android", target_os = "ios")))]
+use std::{env, process};
+
+// These integration tests may be run on their own by issuing:
+// cargo test --test '*'
+
+/// Test spawing a process which then acts as a client to a
+/// one-shot server in the parent process.
+#[cfg(not(any(feature = "force-inprocess", target_os = "android", target_os = "ios")))]
+#[test]
+fn spawn_one_shot_server_client() {
+    let executable_path: String = env!("CARGO_BIN_EXE_spawn_client_test_helper").to_string();
+
+    let (server, token) =
+        IpcOneShotServer::<String>::new().expect("Failed to create IPC one-shot server.");
+
+    let mut command = process::Command::new(executable_path);
+    let child_process = command.arg(token);
+
+    let mut child = child_process
+        .spawn()
+        .expect("Failed to start child process");
+
+    let (_rx, msg) = server.accept().expect("accept failed");
+    assert_eq!("test message", msg);
+
+    let result = child.wait().expect("wait for child process failed");
+    assert!(
+        result.success(),
+        "child process failed with exit status code {}",
+        result.code().expect("exit status code not available")
+    );
+}