chore: improve server integration test output.

This commit adds a few quality of life improvements to the server
integration test:

1. The `--silent` curl arg is removed so that we can get diagnostic info
   from curl on stderr in the event of a failure. Our test only asserts
   on stdout content, which remains unaffected by this change.
2. If the `curl` command invocation status isn't success, we print the
   stderr content enabled by not using `--silent`. This will provide
   more diagnostic context to investigate the failure.
3. The `assert_eq` is changed to assert on a string value created from
   stdout instead of raw bytes. This is easier for humans to diff in the
   test output compared to a slice of byte values.

Combined these changes should make it easier to diagnose future test
failures without needing to iterate in CI.

Author: cpu

tests/tests.rs

@@ -55,15 +55,17 @@ fn server() {
     let output = Command::new("curl")
         .arg("--insecure")
         .arg("--http1.0")
-        .arg("--silent")
         .arg(format!("https://{}", addr))
         .output()
         .expect("cannot run curl");
 
     srv.kill().unwrap();
 
-    println!("client output: {:?}", output.stdout);
-    assert_eq!(output.stdout, b"Try POST /echo\n");
+    if !output.status.success() {
+        println!("curl stderr:\n{}", String::from_utf8_lossy(&output.stderr));
+    }
+
+    assert_eq!(String::from_utf8_lossy(&*output.stdout), "Try POST /echo\n");
 }
 
 #[test]