Macro trillium_testing::assert_headers

macro_rules! assert_headers {
    (@pair, $conn:expr, $header_name:tt, None) => { ... };
    (@pair, $conn:expr, $header_name:tt, $header_value:expr) => { ... };
    ($conn:expr, $($header_name:tt => $header_value:tt,)+) => { ... };
    ($conn:expr, $($header_name:tt => $header_value:tt),*) => { ... };
}

asserts any number of response headers

use trillium_testing::prelude::*;
async fn handler(conn: Conn) -> Conn {
    conn.ok("headers")
        .with_response_header("server", "special-custom-server")
        .with_response_header("request-id", "10")
}

assert_headers!(get("/").on(&handler), "server" => "special-custom-server");
assert_headers!(
    get("/").on(&handler),
    "server" => "special-custom-server",
    "request-id" => "10",
    "content-length" => "7"
);