tests: handle errors properly in examples (#748)

tokio-tls/examples/download-rust-lang.rs

@@ -12,12 +12,12 @@ use native_tls::TlsConnector;
 use tokio::net::TcpStream;
 use tokio::runtime::Runtime;
 
-fn main() {
-    let mut runtime = Runtime::new().unwrap();
-    let addr = "www.rust-lang.org:443".to_socket_addrs().unwrap().next().unwrap();
+fn main() -> Result<(), Box<std::error::Error>> {
+    let mut runtime = Runtime::new()?;
+    let addr = "www.rust-lang.org:443".to_socket_addrs()?.next().ok_or("failed to resolve www.rust-lang.org")?;
 
     let socket = TcpStream::connect(&addr);
-    let cx = TlsConnector::builder().build().unwrap();
+    let cx = TlsConnector::builder().build()?;
     let cx = tokio_tls::TlsConnector::from(cx);
 
     let tls_handshake = socket.and_then(move |socket| {
@@ -36,6 +36,7 @@ fn main() {
         tokio_io::io::read_to_end(socket, Vec::new())
     });
 
-    let (_, data) = runtime.block_on(response).unwrap();
+    let (_, data) = runtime.block_on(response)?;
     println!("{}", String::from_utf8_lossy(&data));
+    Ok(())
 }

tokio-tls/examples/echo.rs

@@ -8,16 +8,16 @@ use tokio::io;
 use tokio::net::TcpListener;
 use tokio::prelude::*;
 
-fn main() {
+fn main() -> Result<(), Box<std::error::Error>> {
     // Bind the server's socket
-    let addr = "127.0.0.1:12345".parse().unwrap();
-    let tcp = TcpListener::bind(&addr).unwrap();
+    let addr = "127.0.0.1:12345".parse()?;
+    let tcp = TcpListener::bind(&addr)?;
 
     // Create the TLS acceptor.
     let der = include_bytes!("identity.p12");
-    let cert = Identity::from_pkcs12(der, "mypass").unwrap();
+    let cert = Identity::from_pkcs12(der, "mypass")?;
     let tls_acceptor = tokio_tls::TlsAcceptor::from(
-        native_tls::TlsAcceptor::builder(cert).build().unwrap());
+        native_tls::TlsAcceptor::builder(cert).build()?);
 
     // Iterate incoming connections
     let server = tcp.incoming().for_each(move |tcp| {
@@ -56,4 +56,5 @@ fn main() {
 
     // Start the runtime and spin up the server
     tokio::run(server);
+    Ok(())
 }