test(event): add tests to tui event module

systeroid-tui/src/event.rs

@@ -1,5 +1,5 @@
 use std::io;
-use std::sync::mpsc::{self, Receiver, RecvError};
+use std::sync::mpsc::{self, Receiver, RecvError, Sender};
 use std::thread;
 use std::time::Duration;
 use termion::event::Key;
@@ -17,6 +17,9 @@ pub enum Event {
 /// [`Event`] handler.
 #[derive(Debug)]
 pub struct EventHandler {
+    /// Sender channel for the events.
+    #[allow(dead_code)]
+    sender: Sender<Event>,
     /// Receiver channel for the events.
     receiver: Receiver<Event>,
 }
@@ -36,11 +39,14 @@ impl EventHandler {
                     .expect("failed to send key input event");
             });
         }
-        thread::spawn(move || loop {
-            sender.send(Event::Tick).expect("failed to send tick event");
-            thread::sleep(tick_rate);
-        });
-        Self { receiver }
+        {
+            let sender = sender.clone();
+            thread::spawn(move || loop {
+                sender.send(Event::Tick).expect("failed to send tick event");
+                thread::sleep(tick_rate);
+            });
+        }
+        Self { sender, receiver }
     }
 
     /// Receives the next event from the channel.
@@ -48,3 +54,39 @@ impl EventHandler {
         self.receiver.recv()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::char;
+    use std::time::Instant;
+
+    const TICK_RATE_MS: u64 = 100;
+
+    #[test]
+    fn test_event() {
+        let start_time = Instant::now();
+        let event_handler = EventHandler::new(TICK_RATE_MS);
+        let mut tick_count = 0;
+        for i in 0..10 {
+            let sender = event_handler.sender.clone();
+            thread::spawn(move || {
+                let key = Key::Char(char::from_digit(i, 10).unwrap_or('9'));
+                let event = Event::KeyPress(key);
+                sender.send(event).unwrap();
+            });
+            match event_handler.next().unwrap() {
+                Event::KeyPress(key) => {
+                    if key == Key::Char('9') {
+                        break;
+                    }
+                }
+                Event::Tick => {
+                    thread::sleep(Duration::from_millis(TICK_RATE_MS));
+                    tick_count += 1;
+                }
+            }
+        }
+        assert!(start_time.elapsed() > Duration::from_millis(tick_count * TICK_RATE_MS));
+    }
+}