Refactor file notification monitoring in tests

Create a `PathWatcher` helper type that presents itself as an `Iterator`
over events on a specified path. It also allows setting a timeout for
waiting for each event, so that it doesn't block indefinately.

Although it watches a specific path, in reality it watches the path's
parent directory, so that it can continue watching the file if it gets
removed and recreated.

1 files changed, 17 insertions, 10 deletions

diff --git a/mullvad-tests/tests/connection.rs b/mullvad-tests/tests/connection.rs
index 91a110fd8a..7ae5efca21 100644
--- a/mullvad-tests/tests/connection.rs
+++ b/mullvad-tests/tests/connection.rs
@@ -10,7 +10,7 @@ use std::sync::mpsc;
 use std::time::Duration;
 
 use mullvad_tests::mock_openvpn::search_openvpn_args;
-use mullvad_tests::{wait_for_file_write_finish, DaemonRunner, MockOpenVpnPluginRpcClient};
+use mullvad_tests::{watch_event, DaemonRunner, MockOpenVpnPluginRpcClient, PathWatcher};
 use mullvad_types::states::{DaemonState, SecurityState, TargetState};
 
 #[cfg(target_os = "linux")]
@@ -44,15 +44,14 @@ fn spawns_openvpn() {
     let mut daemon = DaemonRunner::spawn();
     let mut rpc_client = daemon.rpc_client().unwrap();
     let openvpn_args_file = daemon.mock_openvpn_args_file();
+    let mut openvpn_args_file_events = PathWatcher::watch(&openvpn_args_file).unwrap();
 
     assert!(!openvpn_args_file.exists());
 
     rpc_client.set_account(Some("123456".to_owned())).unwrap();
     rpc_client.connect().unwrap();
 
-    wait_for_file_write_finish(&openvpn_args_file, Duration::from_secs(5));
-
-    assert!(openvpn_args_file.exists());
+    openvpn_args_file_events.assert_create_write_close_sequence();
 }
 
 #[test]
@@ -60,20 +59,22 @@ fn respawns_openvpn_if_it_crashes() {
     let mut daemon = DaemonRunner::spawn();
     let mut rpc_client = daemon.rpc_client().unwrap();
     let openvpn_args_file = daemon.mock_openvpn_args_file();
+    let mut openvpn_args_file_events = PathWatcher::watch(&openvpn_args_file).unwrap();
+
+    openvpn_args_file_events.set_timeout(Duration::from_secs(10));
 
     assert!(!openvpn_args_file.exists());
 
     rpc_client.set_account(Some("123456".to_owned())).unwrap();
     rpc_client.connect().unwrap();
 
-    wait_for_file_write_finish(&openvpn_args_file, Duration::from_secs(5));
+    openvpn_args_file_events.assert_create_write_close_sequence();
 
     // Stop OpenVPN by removing the mock OpenVPN arguments file
     fs::remove_file(&openvpn_args_file).expect("Failed to remove the mock OpenVPN arguments file");
+    assert_eq!(openvpn_args_file_events.next(), Some(watch_event::REMOVE));
 
-    wait_for_file_write_finish(&openvpn_args_file, Duration::from_secs(5));
-
-    assert!(openvpn_args_file.exists());
+    openvpn_args_file_events.assert_create_write_close_sequence();
 }
 
 #[test]
@@ -189,12 +190,14 @@ fn returns_to_connecting_state() {
     let mut daemon = DaemonRunner::spawn();
     let mut rpc_client = daemon.rpc_client().unwrap();
     let openvpn_args_file = daemon.mock_openvpn_args_file();
+    let mut openvpn_args_file_events = PathWatcher::watch(&openvpn_args_file).unwrap();
     let state_events = rpc_client.new_state_subscribe().unwrap();
 
     rpc_client.set_account(Some("123456".to_owned())).unwrap();
     rpc_client.connect().unwrap();
 
     assert_state_event(&state_events, CONNECTING_STATE);
+    openvpn_args_file_events.assert_create_write_close_sequence();
 
     let mut mock_plugin_client = create_mock_openvpn_plugin_client(openvpn_args_file);
 
@@ -206,7 +209,8 @@ fn returns_to_connecting_state() {
     mock_plugin_client.route_predown().unwrap();
 
     // Wait for new OpenVPN instance
-    wait_for_file_write_finish(&openvpn_args_file, Duration::from_secs(5));
+    assert_eq!(openvpn_args_file_events.next(), Some(watch_event::REMOVE));
+    openvpn_args_file_events.assert_create_write_close_sequence();
 
     assert_state_event(&state_events, CONNECTING_STATE);
     assert_eq!(rpc_client.get_state().unwrap(), CONNECTING_STATE);
@@ -265,7 +269,10 @@ fn create_mock_openvpn_plugin_client<P: AsRef<Path>>(
 fn get_plugin_arguments<P: AsRef<Path>>(openvpn_args_file_path: P) -> (String, String) {
     let args_file_path = openvpn_args_file_path.as_ref();
 
-    wait_for_file_write_finish(&args_file_path, Duration::from_secs(5));
+    if !args_file_path.exists() {
+        let _wait_for_args_file = PathWatcher::watch(&args_file_path)
+            .map(|mut events| events.find(|&event| event == watch_event::CLOSE_WRITE));
+    }
 
     let mut arguments = search_openvpn_args(&args_file_path, OPENVPN_PLUGIN_NAME).skip(1);