Rollup merge of rust-lang#35140 - the-kenny:tcp-stress-test-const-thr…

…ead-count, r=alexcrichton

tcp-stress-test: Pull out thread count as a constant

This PR factors out the number of concurrent threads used in `tcp-stress-test.rs` to a constant at the top of the file.

We at @NixOS had to lower our thread count as the chrooted-builds don't allow that many threads.

This change will make it easier to lower/increase the count in the future (I actually forgot to change the second `1000` when I was working on this). Another benefit is the removal of magic numbers in the test suite.

This is related to rust-lang#35107

src/test/run-pass/tcp-stress.rs

@@ -21,6 +21,8 @@ use std::sync::mpsc::channel;
 use std::time::Duration;
 use std::thread::{self, Builder};
 
+const TARGET_CNT: usize = 200;
+
 fn main() {
     // This test has a chance to time out, try to not let it time out
     thread::spawn(move|| -> () {
@@ -42,8 +44,9 @@ fn main() {
     });
 
     let (tx, rx) = channel();
+
     let mut spawned_cnt = 0;
-    for _ in 0..1000 {
+    for _ in 0..TARGET_CNT {
         let tx = tx.clone();
         let res = Builder::new().stack_size(64 * 1024).spawn(move|| {
             match TcpStream::connect(addr) {
@@ -66,6 +69,6 @@ fn main() {
     for _ in 0..spawned_cnt {
         rx.recv().unwrap();
     }
-    assert_eq!(spawned_cnt, 1000);
+    assert_eq!(spawned_cnt, TARGET_CNT);
     process::exit(0);
 }