Fix behavior when connecting wss url without TLS support (#437)

* Fail before connecting if TLS support is not present

* Add test for wss:// explicit failure when TLS support is not compiled in

* Fix: do not compile irrelevant test when  feature is not enabled

src/client.rs

@@ -52,6 +52,12 @@ pub fn connect_with_config<Req: IntoClientRequest>(
     ) -> Result<(WebSocket<MaybeTlsStream<TcpStream>>, Response)> {
         let uri = request.uri();
         let mode = uri_mode(uri)?;
+
+        #[cfg(not(any(feature = "native-tls", feature = "__rustls-tls")))]
+        if let Mode::Tls = mode {
+            return Err(Error::Url(UrlError::TlsFeatureNotEnabled));
+        }
+
         let host = request.uri().host().ok_or(Error::Url(UrlError::NoHostName))?;
         let host = if host.starts_with('[') { &host[1..host.len() - 1] } else { host };
         let port = uri.port_u16().unwrap_or(match mode {

tests/wss_fails_when_no_tls.rs

@@ -0,0 +1,10 @@
+#![cfg(all(feature = "handshake", not(any(feature = "native-tls", feature = "__rustls-tls"))))]
+
+use tungstenite::{connect, error::UrlError, Error};
+
+#[test]
+fn wss_url_fails_when_no_tls_support() {
+    let ws = connect("wss://127.0.0.1/ws");
+    eprintln!("{:?}", ws);
+    assert!(matches!(ws, Err(Error::Url(UrlError::TlsFeatureNotEnabled))))
+}