actix-test: allow dynamic port setting (#2960)

Co-authored-by: Rob Ede <robjtede@icloud.com>

actix-test/CHANGES.md

@@ -2,6 +2,7 @@
 
 ## Unreleased - 2022-xx-xx
 
+- Add `TestServerConfig::port()` setter method.
 - Minimum supported Rust version (MSRV) is now 1.59 due to transitive `time` dependency.
 
 ## 0.1.0 - 2022-07-24

actix-test/src/lib.rs

@@ -145,7 +145,7 @@ where
     // run server in separate orphaned thread
     thread::spawn(move || {
         rt::System::new().block_on(async move {
-            let tcp = net::TcpListener::bind("127.0.0.1:0").unwrap();
+            let tcp = net::TcpListener::bind(("127.0.0.1", cfg.port)).unwrap();
             let local_addr = tcp.local_addr().unwrap();
             let factory = factory.clone();
             let srv_cfg = cfg.clone();
@@ -390,6 +390,7 @@ pub struct TestServerConfig {
     tp: HttpVer,
     stream: StreamType,
     client_request_timeout: Duration,
+    port: u16,
 }
 
 impl Default for TestServerConfig {
@@ -405,6 +406,7 @@ impl TestServerConfig {
             tp: HttpVer::Both,
             stream: StreamType::Tcp,
             client_request_timeout: Duration::from_secs(5),
+            port: 0,
         }
     }
 
@@ -439,6 +441,14 @@ impl TestServerConfig {
         self.client_request_timeout = dur;
         self
     }
+
+    /// Sets test server port.
+    ///
+    /// By default, a random free port is determined by the OS.
+    pub fn port(mut self, port: u16) -> Self {
+        self.port = port;
+        self
+    }
 }
 
 /// A basic HTTP server controller that simplifies the process of writing integration tests for