feat: add api to get the hash of a file (#375)

tests/http.rs

@@ -189,6 +189,21 @@ fn head_file(server: TestServer) -> Result<(), Error> {
     Ok(())
 }
 
+#[rstest]
+fn hash_file(server: TestServer) -> Result<(), Error> {
+    let resp = reqwest::blocking::get(format!("{}index.html?hash", server.url()))?;
+    assert_eq!(
+        resp.headers().get("content-type").unwrap(),
+        "text/html; charset=utf-8"
+    );
+    assert_eq!(resp.status(), 200);
+    assert_eq!(
+        resp.text()?,
+        "c8dd395e3202674b9512f7b7f956e0d96a8ba8f572e785b0d5413ab83766dbc4"
+    );
+    Ok(())
+}
+
 #[rstest]
 fn get_file_404(server: TestServer) -> Result<(), Error> {
     let resp = reqwest::blocking::get(format!("{}404", server.url()))?;