feat(serve): support `--port 0` to use an open port (#23846)

Closes https://github.com/denoland/deno/issues/23845

1 files changed, 51 insertions, 0 deletions

diff --git a/tests/integration/serve_tests.rs b/tests/integration/serve_tests.rs
new file mode 100644
index 000000000..92b0576ed
--- /dev/null
+++ b/tests/integration/serve_tests.rs
@@ -0,0 +1,51 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+
+use std::io::Read;
+
+use deno_fetch::reqwest;
+use pretty_assertions::assert_eq;
+use regex::Regex;
+use test_util as util;
+
+#[tokio::test]
+async fn deno_serve_port_0() {
+  let mut child = util::deno_cmd()
+    .current_dir(util::testdata_path())
+    .arg("serve")
+    .arg("--port")
+    .arg("0")
+    .arg("./serve.ts")
+    .stdout_piped()
+    .spawn()
+    .unwrap();
+  let stdout = child.stdout.as_mut().unwrap();
+  let mut buffer = [0; 50];
+  let _read = stdout.read(&mut buffer).unwrap();
+  let msg = std::str::from_utf8(&buffer).unwrap();
+  let port_regex = Regex::new(r"(\d+)").unwrap();
+  let port = port_regex.find(msg).unwrap().as_str();
+
+  let cert = reqwest::Certificate::from_pem(include_bytes!(
+    "../testdata/tls/RootCA.crt"
+  ))
+  .unwrap();
+
+  let client = reqwest::Client::builder()
+    .add_root_certificate(cert)
+    .http2_prior_knowledge()
+    .build()
+    .unwrap();
+
+  let res = client
+    .get(&format!("http://127.0.0.1:{port}"))
+    .send()
+    .await
+    .unwrap();
+  assert_eq!(200, res.status());
+
+  let body = res.text().await.unwrap();
+  assert_eq!(body, "deno serve --port 0 works!");
+
+  child.kill().unwrap();
+  child.wait().unwrap();
+}