e2e_tests: Add vsock tests

Add vsock tests to confirm the vsock device works at crosvm upstream

BUG=b:254375643
TEST=`./tools/presubmit`

Change-Id: I24137e00dc449c97be8ee7e9101906541ea843d1
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/3998914
Reviewed-by: Takaya Saeki <takayas@chromium.org>
Commit-Queue: Ryuichiro Chiba <chibar@chromium.org>
Reviewed-by: Keiichi Watanabe <keiichiw@chromium.org>

e2e_tests/tests/vsock.rs

@@ -0,0 +1,86 @@
+// Copyright 2022 The ChromiumOS Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+//! Testing vsock.
+
+pub mod fixture;
+
+use std::process::Command;
+use std::process::Stdio;
+use std::thread;
+use std::time::Duration;
+
+use fixture::Config;
+use fixture::TestVm;
+
+const HOST_CID: u64 = 2;
+const GUEST_CID: u64 = 5;
+const VSOCK_COM_PORT: u64 = 11111;
+
+const SERVER_TIMEOUT_IN_SEC: u64 = 3;
+const CLIENT_WAIT_DURATION: Duration = Duration::from_millis(1000);
+
+const MESSAGE_TO_HOST: &str = "Connection from the host is successfully established";
+const MESSAGE_TO_GUEST: &str = "Connection from the guest is successfully established";
+
+#[test]
+fn host_to_guest_connection() {
+    let config = Config::new().extra_args(vec!["--cid".to_string(), GUEST_CID.to_string()]);
+    let mut vm = TestVm::new(config).unwrap();
+
+    let handle_guest = thread::spawn(move || {
+        let cmd = format!(
+            "echo {MESSAGE_TO_HOST} | timeout {SERVER_TIMEOUT_IN_SEC}s ncat -l --vsock {VSOCK_COM_PORT}",
+        );
+        vm.exec_in_guest(&cmd).unwrap();
+    });
+
+    // wait until the server is ready
+    thread::sleep(CLIENT_WAIT_DURATION);
+
+    let output = Command::new("ncat")
+        .args(["--idle-timeout", "1"])
+        .args([
+            "--vsock",
+            &GUEST_CID.to_string(),
+            &VSOCK_COM_PORT.to_string(),
+        ])
+        .output()
+        .expect("failed to execute process");
+    let host_stdout = std::str::from_utf8(&output.stdout).unwrap();
+
+    handle_guest.join().unwrap();
+
+    assert_eq!(host_stdout.trim(), MESSAGE_TO_HOST);
+}
+
+#[test]
+fn guest_to_host_connection() {
+    let config = Config::new().extra_args(vec!["--cid".to_string(), GUEST_CID.to_string()]);
+    let mut vm = TestVm::new(config).unwrap();
+
+    let echo = Command::new("echo")
+        .arg(MESSAGE_TO_GUEST)
+        .stdout(Stdio::piped())
+        .spawn()
+        .unwrap();
+    let mut handle_host = Command::new("timeout")
+        .arg(format!("{SERVER_TIMEOUT_IN_SEC}s"))
+        .arg("ncat")
+        .arg("-l")
+        .args(["--vsock", &VSOCK_COM_PORT.to_string()])
+        .stdin(echo.stdout.unwrap())
+        .spawn()
+        .expect("failed to execute process");
+
+    // wait until the server is ready
+    thread::sleep(CLIENT_WAIT_DURATION);
+
+    let cmd = format!("ncat --idle-timeout 1 --vsock {HOST_CID} {VSOCK_COM_PORT}");
+    let guest_stdout = vm.exec_in_guest(&cmd).unwrap();
+
+    handle_host.wait().unwrap();
+
+    assert_eq!(guest_stdout.trim(), MESSAGE_TO_GUEST);
+}