test(monitor_reconciliator): add initial tests

Added a test for sending a MonitorNotification using the
send_notification function. The test sends a MonitorNotification and
tests that the notification was recieved using event_rx.

Added a test for inserting a monitor into the cache. The test creates
a monitor and uses the insert_in_monitor_cache function to insert the
monitor into cache, and will attempt to retrieve the monitor from the
cache and check to see if it matches the expected value.

Addaded a test for channel capacity. The test will send 20 notifications
and then another notification, then check to ensure that all 20
messages match the notification we sent. The test will also check to
ensure the last notification sent wasn't received.

Added a test for the notification listener. The test will create a
window manager and setup the notification listener, then check to see if
we can send a notification and receive the notification.

Created a Mock Monitor that can be used with testing functions that call
the Win32 API.

Added a test for the attach_display_devices function. The test will
create a Mock Monitor and add the monitor to a closure that simulates a
display_provider. The test passes the display_provider into the
attach_display_devices function and checks to ensure we recieve the
monitor we passed in.

komorebi/src/monitor_reconciliator/mod.rs

@@ -29,7 +29,7 @@ use std::sync::OnceLock;
 
 pub mod hidden;
 
-#[derive(Debug, Copy, Clone, Serialize, Deserialize)]
+#[derive(Debug, Copy, Clone, Serialize, Deserialize, PartialEq)]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
 #[serde(tag = "type", content = "content")]
 pub enum MonitorNotification {
@@ -727,3 +727,304 @@ where
 
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::window_manager_event::WindowManagerEvent;
+    use crossbeam_channel::bounded;
+    use crossbeam_channel::Sender;
+    use std::path::PathBuf;
+    use uuid::Uuid;
+    use windows::Win32::Devices::Display::DISPLAYCONFIG_VIDEO_OUTPUT_TECHNOLOGY;
+    // NOTE: Using RECT instead of RECT since I get a mismatched type error. Can be updated if
+    // needed.
+    use windows::Win32::Foundation::RECT;
+
+    // Creating a Mock Display Provider
+    #[derive(Clone)]
+    struct MockDevice {
+        hmonitor: isize,
+        device_path: String,
+        device_name: String,
+        device_description: String,
+        serial_number_id: Option<String>,
+        size: RECT,
+        work_area_size: RECT,
+        device_key: String,
+        output_technology: Option<DISPLAYCONFIG_VIDEO_OUTPUT_TECHNOLOGY>,
+    }
+
+    impl From<MockDevice> for win32_display_data::Device {
+        fn from(mock: MockDevice) -> Self {
+            win32_display_data::Device {
+                hmonitor: mock.hmonitor,
+                device_path: mock.device_path,
+                device_name: mock.device_name,
+                device_description: mock.device_description,
+                serial_number_id: mock.serial_number_id,
+                size: mock.size,
+                work_area_size: mock.work_area_size,
+                device_key: mock.device_key,
+                output_technology: mock.output_technology,
+            }
+        }
+    }
+
+    // Creating a Window Manager Instance
+    struct TestContext {
+        socket_path: Option<PathBuf>,
+    }
+
+    impl Drop for TestContext {
+        fn drop(&mut self) {
+            if let Some(socket_path) = &self.socket_path {
+                // Clean up the socket file
+                if let Err(e) = std::fs::remove_file(socket_path) {
+                    tracing::warn!("Failed to remove socket file: {}", e);
+                }
+            }
+        }
+    }
+
+    fn setup_window_manager() -> (WindowManager, TestContext) {
+        let (_sender, receiver): (Sender<WindowManagerEvent>, Receiver<WindowManagerEvent>) =
+            bounded(1);
+
+        // Temporary socket path for testing
+        let socket_name = format!("komorebi-test-{}.sock", Uuid::new_v4());
+        let socket_path = PathBuf::from(socket_name);
+
+        // Create a new WindowManager instance
+        let wm = match WindowManager::new(receiver, Some(socket_path.clone())) {
+            Ok(manager) => manager,
+            Err(e) => {
+                panic!("Failed to create WindowManager: {}", e);
+            }
+        };
+
+        (
+            wm,
+            TestContext {
+                socket_path: Some(socket_path),
+            },
+        )
+    }
+
+    #[test]
+    fn test_send_notification() {
+        // Create a monitor notification
+        let notification = MonitorNotification::ResolutionScalingChanged;
+
+        // Use the send_notification function to send the notification
+        send_notification(notification);
+
+        // Receive the notification from the channel
+        let received = event_rx().try_recv();
+
+        // Check if we received the notification and if it matches what we sent
+        match received {
+            Ok(notification) => {
+                assert_eq!(notification, MonitorNotification::ResolutionScalingChanged);
+            }
+            Err(e) => panic!("Failed to receive MonitorNotification: {}", e),
+        }
+    }
+
+    #[test]
+    fn test_channel_bounded_capacity() {
+        let (_, receiver) = channel();
+
+        // Fill the channel to its capacity (20 messages)
+        for _ in 0..20 {
+            send_notification(MonitorNotification::WorkAreaChanged);
+        }
+
+        // Attempt to send another message (should be dropped)
+        send_notification(MonitorNotification::ResolutionScalingChanged);
+
+        // Verify the channel contains only the first 20 messages
+        for _ in 0..20 {
+            let notification = match receiver.try_recv() {
+                Ok(notification) => notification,
+                Err(e) => panic!("Failed to receive MonitorNotification: {}", e),
+            };
+            assert_eq!(
+                notification,
+                MonitorNotification::WorkAreaChanged,
+                "Unexpected notification in the channel"
+            );
+        }
+
+        // Verify that no additional messages are in the channel
+        assert!(
+            receiver.try_recv().is_err(),
+            "Channel should be empty after consuming all messages"
+        );
+    }
+
+    #[test]
+    fn test_insert_in_monitor_cache() {
+        let m = monitor::new(
+            0,
+            Rect::default(),
+            Rect::default(),
+            "Test Monitor".to_string(),
+            "Test Device".to_string(),
+            "Test Device ID".to_string(),
+            Some("TestMonitorID".to_string()),
+        );
+
+        // Insert the monitor into the cache
+        insert_in_monitor_cache("TestMonitorID", m.clone());
+
+        // Retrieve the monitor from the cache
+        let cache = MONITOR_CACHE
+            .get_or_init(|| Mutex::new(HashMap::new()))
+            .lock();
+        let retrieved_monitor = cache.get("TestMonitorID");
+
+        // Check that the monitor was inserted correctly and matches the expected value
+        assert_eq!(retrieved_monitor, Some(&m));
+    }
+
+    #[test]
+    fn test_insert_two_monitors_cache() {
+        let m1 = monitor::new(
+            0,
+            Rect::default(),
+            Rect::default(),
+            "Test Monitor".to_string(),
+            "Test Device".to_string(),
+            "Test Device ID".to_string(),
+            Some("TestMonitorID".to_string()),
+        );
+
+        let m2 = monitor::new(
+            0,
+            Rect::default(),
+            Rect::default(),
+            "Test Monitor 2".to_string(),
+            "Test Device 2".to_string(),
+            "Test Device ID 2".to_string(),
+            Some("TestMonitorID2".to_string()),
+        );
+
+        // Insert the first monitor into the cache
+        insert_in_monitor_cache("TestMonitorID", m1.clone());
+
+        // Insert the second monitor into the cache
+        insert_in_monitor_cache("TestMonitorID2", m2.clone());
+
+        // Retrieve the cache to check if the first and second monitors are present
+        let cache = MONITOR_CACHE
+            .get_or_init(|| Mutex::new(HashMap::new()))
+            .lock();
+
+        // Check if Monitor 1 was found in the cache
+        assert_eq!(
+            cache.get("TestMonitorID"),
+            Some(&m1),
+            "Monitor cache should contain monitor 1"
+        );
+
+        // Check if Monitor 2 was found in the cache
+        assert_eq!(
+            cache.get("TestMonitorID2"),
+            Some(&m2),
+            "Monitor cache should contain monitor 2"
+        );
+    }
+
+    #[test]
+    fn test_listen_for_notifications() {
+        // Create a WindowManager instance for testing
+        let (wm, _test_context) = setup_window_manager();
+
+        // Start the notification listener
+        let result = listen_for_notifications(Arc::new(Mutex::new(wm)));
+
+        // Check if the listener started successfully
+        assert!(result.is_ok(), "Failed to start notification listener");
+
+        // Test sending a notification
+        send_notification(MonitorNotification::DisplayConnectionChange);
+
+        // Receive the notification from the channel
+        let received = event_rx().try_recv();
+
+        // Check if we received the notification and if it matches what we sent
+        match received {
+            Ok(notification) => {
+                assert_eq!(notification, MonitorNotification::DisplayConnectionChange);
+            }
+            Err(e) => panic!("Failed to receive MonitorNotification: {}", e),
+        }
+    }
+
+    #[test]
+    fn test_attached_display_devices() {
+        // Define mock display data
+        let mock_monitor = MockDevice {
+            hmonitor: 1,
+            device_path: String::from(
+                "\\\\?\\DISPLAY#ABC123#4&123456&0&UID0#{saucepackets-4321-5678-2468-abc123456789}",
+            ),
+            device_name: String::from("\\\\.\\DISPLAY1"),
+            device_description: String::from("Display description"),
+            serial_number_id: Some(String::from("SaucePackets123")),
+            device_key: String::from("Mock Key"),
+            size: RECT {
+                left: 0,
+                top: 0,
+                right: 1920,
+                bottom: 1080,
+            },
+            work_area_size: RECT {
+                left: 0,
+                top: 0,
+                right: 1920,
+                bottom: 1080,
+            },
+            output_technology: Some(DISPLAYCONFIG_VIDEO_OUTPUT_TECHNOLOGY(0)),
+        };
+
+        // Create a closure to simulate the display provider
+        let display_provider = || {
+            vec![Ok::<win32_display_data::Device, win32_display_data::Error>(
+                win32_display_data::Device::from(mock_monitor.clone()),
+            )]
+            .into_iter()
+        };
+
+        // Should contain the mock monitor
+        let result = attached_display_devices(display_provider).ok();
+        if let Some(monitors) = result {
+            // Check Number of monitors
+            assert_eq!(monitors.len(), 1, "Expected one monitor");
+
+            // hmonitor
+            assert_eq!(monitors[0].id(), 1);
+
+            // device name
+            assert_eq!(monitors[0].name(), &String::from("DISPLAY1"));
+
+            // Device
+            assert_eq!(monitors[0].device(), &String::from("ABC123"));
+
+            // Device ID
+            assert_eq!(
+                monitors[0].device_id(),
+                &String::from("ABC123-4&123456&0&UID0")
+            );
+
+            // Check monitor serial number id
+            assert_eq!(
+                monitors[0].serial_number_id,
+                Some(String::from("SaucePackets123")),
+            );
+        } else {
+            panic!("No monitors found");
+        }
+    }
+}