- update: database client to implement a database trait so we can mock it out

- update unit tests
- add: database client mock

auth-service/src/users.rs

@@ -1,4 +1,4 @@
-use crate::database_client::DatabaseClient;
+use crate::database_client::{DatabaseClient, DatabaseClientTrait};
 
 use argon2::{
     password_hash::{
@@ -19,7 +19,7 @@ pub fn verify_password(password: &str, hash: &str) -> bool {
     Argon2::default().verify_password(password.as_bytes(), &parsed_hash).is_ok()
 }
 
-pub async fn verify_user(mut db_client: DatabaseClient,
+pub async fn verify_user<T: DatabaseClientTrait>(mut db_client: T,
                          username: &str, password: &str) -> Option<String> {
     // Placeholder: Replace with a gRPC call to the Database Service
     let user = db_client.get_user_by_username(username).await.ok()?;