[commtest][identity] Add test for FindUserID RPC

Summary:
Added integration test for FindUserID RPC added in D9834.

Depends on D9834

Test Plan: The test passes locally and on CI

Reviewers: kamil, michal, varun, wyilio

Reviewed By: varun

Subscribers: ashoat, tomek, wyilio

Differential Revision: https://phab.comm.dev/D9835

services/commtest/run-tests-ci.sh

@@ -51,6 +51,7 @@ run_test "backup*"
 run_test "tunnelbroker_*" --test-threads=1
 run_test grpc_client_test
 # below tests are flaky and need to be run in order
+run_test identity_integration_tests
 run_test identity_keyserver_tests
 run_test identity_access_tokens_tests
 run_test identity_one_time_key_tests

services/commtest/tests/identity_integration_tests.rs

@@ -0,0 +1,40 @@
+use commtest::identity::device::{
+  create_device, DEVICE_TYPE, PLACEHOLDER_CODE_VERSION,
+};
+use commtest::service_addr;
+use grpc_clients::identity::protos::authenticated::find_user_id_request::Identifier;
+use grpc_clients::identity::{
+  get_auth_client, protos::authenticated::FindUserIdRequest,
+};
+
+#[tokio::test]
+async fn find_user_id_by_username() {
+  let device_info = create_device(None).await;
+
+  let mut client = get_auth_client(
+    &service_addr::IDENTITY_GRPC.to_string(),
+    device_info.user_id.clone(),
+    device_info.device_id,
+    device_info.access_token,
+    PLACEHOLDER_CODE_VERSION,
+    DEVICE_TYPE.to_string(),
+  )
+  .await
+  .expect("Couldn't connect to identity service");
+
+  let request = FindUserIdRequest {
+    identifier: Some(Identifier::Username(device_info.username)),
+  };
+
+  let response = client
+    .find_user_id(request)
+    .await
+    .expect("Request failed")
+    .into_inner();
+
+  assert_eq!(
+    response.user_id,
+    Some(device_info.user_id),
+    "User ID should match"
+  );
+}