Apply deadline across redirects. (#313)

Previously, each redirect could take timeout time, so a series of slow
redirects could run for longer than expected, or indefinitely.

src/test/redirect.rs

@@ -1,6 +1,8 @@
 use std::{
     io::{self, Write},
     net::TcpStream,
+    thread,
+    time::Duration,
 };
 use testserver::{self, TestServer};
 
@@ -158,6 +160,31 @@ fn redirect_308() {
     assert_eq!(resp.get_url(), "test://host/valid_response");
 }
 
+#[test]
+fn redirects_hit_timeout() {
+    // A chain of 2 redirects and an OK, each of which takes 50ms; we set a
+    // timeout of 100ms and should error.
+    test::set_handler("/redirect_sleep1", |_| {
+        thread::sleep(Duration::from_millis(50));
+        test::make_response(302, "Go here", vec!["Location: /redirect_sleep2"], vec![])
+    });
+    test::set_handler("/redirect_sleep2", |_| {
+        thread::sleep(Duration::from_millis(50));
+        test::make_response(302, "Go here", vec!["Location: /ok"], vec![])
+    });
+    test::set_handler("/ok", |_| {
+        thread::sleep(Duration::from_millis(50));
+        test::make_response(200, "Go here", vec![], vec![])
+    });
+    let req = crate::builder().timeout(Duration::from_millis(100)).build();
+    let result = req.get("test://host/redirect_sleep1").call();
+    assert!(
+        matches!(result, Err(Error::Transport(_))),
+        "expected Transport error, got {:?}",
+        result
+    );
+}
+
 #[test]
 fn too_many_redirects() {
     for i in 0..10_000 {