add test case

tests/client.rs

@@ -54,6 +54,28 @@ async fn auto_headers() {
     assert_eq!(res.remote_addr(), Some(server.addr()));
 }
 
+#[tokio::test]
+async fn donot_set_conent_length_0_if_have_no_body() {
+    let server = server::http(move |req| async move {
+        let headers = req.headers();
+        assert_eq!(headers.get("content-length"), None);
+        dbg!(&headers);
+        http::Response::default()
+    });
+
+    let url = format!("http://{}/conent-length", server.addr());
+    let res = reqwest::Client::builder()
+        .no_proxy()
+        .build()
+        .expect("client builder")
+        .get(&url)
+        .send()
+        .await
+        .expect("request");
+
+    assert_eq!(res.status(), reqwest::StatusCode::OK);
+}
+
 #[tokio::test]
 async fn user_agent() {
     let server = server::http(move |req| async move {