add random string generator

packages/backend/native-utils/crates/util/Cargo.toml

@@ -8,4 +8,5 @@ edition = "2021"
 [dependencies]
 cuid2 = "0.1.0"
 once_cell = "1.17.1"
+rand = "0.8.5"
 thiserror = "1.0.40"

packages/backend/native-utils/crates/util/src/lib.rs

@@ -1 +1,2 @@
 pub mod id;
+pub mod random;

packages/backend/native-utils/crates/util/src/random.rs

@@ -0,0 +1,25 @@
+use rand::{distributions::Alphanumeric, thread_rng, Rng};
+
+pub fn gen_string(length: u16) -> String {
+    thread_rng()
+        .sample_iter(Alphanumeric)
+        .take(length.into())
+        .map(char::from)
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use std::thread;
+
+    use super::gen_string;
+
+    #[test]
+    fn can_generate_string() {
+        assert_eq!(gen_string(16).len(), 16);
+        assert_ne!(gen_string(16), gen_string(16));
+        let s1 = thread::spawn(|| gen_string(16));
+        let s2 = thread::spawn(|| gen_string(16));
+        assert_ne!(s1.join().unwrap(), s2.join().unwrap());
+    }
+}