test(header): change test_headers_show to use str.contains

src/header/mod.rs

@@ -658,13 +658,8 @@ mod tests {
         headers.set(Host { hostname: "foo.bar".to_owned(), port: None });
 
         let s = headers.to_string();
-        // hashmap's iterators have arbitrary order, so we must sort first
+        assert!(s.contains("Host: foo.bar\r\n"));
-        let mut pieces = s.split("\r\n").collect::<Vec<&str>>();
+        assert!(s.contains("Content-Length: 15\r\n"));
-        pieces.sort();
-        assert_eq!(pieces.len(), 3);
-        assert_eq!(pieces[0], "Host: foo.bar");
-        assert_eq!(pieces[1], "Content-Length: 15");
-        assert_eq!(pieces[2], ""); // trailing \r\n
     }
 
     #[test]