diff --git a/src/ui/mod.rs b/src/ui/mod.rs
index f77092d..ba51e35 100644
--- a/src/ui/mod.rs
+++ b/src/ui/mod.rs
@@ -12,6 +12,8 @@ mod setup_test;
 #[cfg(test)]
 mod curriculum_test;
 pub mod systems;
+#[cfg(test)]
+mod systems_test;
 pub mod target;
 
 use bevy::prelude::*;
diff --git a/src/ui/systems_test.rs b/src/ui/systems_test.rs
new file mode 100644
index 0000000..c58159f
--- /dev/null
+++ b/src/ui/systems_test.rs
@@ -0,0 +1,129 @@
+//! Tests for the UI systems module.
+#[cfg(test)]
+mod tests {
+    use bevy::prelude::*;
+    use crate::components::RhythmModeButton;
+    use crate::resources::{RhythmState, RhythmMode};
+    use crate::ui::systems::rhythm_mode_toggle_system;
+
+    fn setup_app() -> App {
+        let mut app = App::new();
+        // Since bevy::core doesn't have it and it's not in prelude let's just use MinimalPlugins to set up App schedule.
+        app.add_plugins(MinimalPlugins);
+        app
+    }
+
+    #[test]
+    fn test_rhythm_mode_toggle_system_pressed_constant_to_accelerate() {
+        let mut app = setup_app();
+
+        app.insert_resource(RhythmState {
+            mode: RhythmMode::Constant,
+            duration: 1.0,
+            accelerate_counter: 5,
+        });
+
+        app.add_systems(Update, rhythm_mode_toggle_system);
+
+        let text_entity = app.world_mut().spawn(Text::new("Rhythm: Constant")).id();
+        let _button_entity = app.world_mut().spawn((
+            RhythmModeButton,
+            Interaction::Pressed,
+            BackgroundColor(Color::NONE),
+        )).add_child(text_entity).id();
+
+        app.update();
+
+        let state = app.world().resource::<RhythmState>();
+        assert_eq!(state.mode, RhythmMode::Accelerate);
+        assert_eq!(state.accelerate_counter, 0);
+
+        let text = app.world().get::<Text>(text_entity).unwrap();
+        assert_eq!(text.0, "Rhythm: Accelerate");
+    }
+
+    #[test]
+    fn test_rhythm_mode_toggle_system_pressed_accelerate_to_constant() {
+        let mut app = setup_app();
+
+        app.insert_resource(RhythmState {
+            mode: RhythmMode::Accelerate,
+            duration: 1.0,
+            accelerate_counter: 8,
+        });
+
+        app.add_systems(Update, rhythm_mode_toggle_system);
+
+        let text_entity = app.world_mut().spawn(Text::new("Rhythm: Accelerate")).id();
+        let _button_entity = app.world_mut().spawn((
+            RhythmModeButton,
+            Interaction::Pressed,
+            BackgroundColor(Color::NONE),
+        )).add_child(text_entity).id();
+
+        app.update();
+
+        let state = app.world().resource::<RhythmState>();
+        assert_eq!(state.mode, RhythmMode::Constant);
+        assert_eq!(state.accelerate_counter, 0);
+
+        let text = app.world().get::<Text>(text_entity).unwrap();
+        assert_eq!(text.0, "Rhythm: Constant");
+    }
+
+    #[test]
+    fn test_rhythm_mode_toggle_system_hovered() {
+        let mut app = setup_app();
+
+        app.insert_resource(RhythmState {
+            mode: RhythmMode::Constant,
+            duration: 1.0,
+            accelerate_counter: 0,
+        });
+
+        app.add_systems(Update, rhythm_mode_toggle_system);
+
+        let text_entity = app.world_mut().spawn(Text::new("Rhythm: Constant")).id();
+        let button_entity = app.world_mut().spawn((
+            RhythmModeButton,
+            Interaction::Hovered,
+            BackgroundColor(Color::NONE),
+        )).add_child(text_entity).id();
+
+        app.update();
+
+        let state = app.world().resource::<RhythmState>();
+        assert_eq!(state.mode, RhythmMode::Constant); // Should not change
+
+        let background = app.world().get::<BackgroundColor>(button_entity).unwrap();
+        assert_eq!(background.0, Color::srgba(0.886, 0.886, 0.886, 0.1));
+    }
+
+    #[test]
+    fn test_rhythm_mode_toggle_system_none() {
+        let mut app = setup_app();
+
+        app.insert_resource(RhythmState {
+            mode: RhythmMode::Constant,
+            duration: 1.0,
+            accelerate_counter: 0,
+        });
+
+        app.add_systems(Update, rhythm_mode_toggle_system);
+
+        let text_entity = app.world_mut().spawn(Text::new("Rhythm: Constant")).id();
+        let button_entity = app.world_mut().spawn((
+            RhythmModeButton,
+            Interaction::None,
+            BackgroundColor(Color::srgba(0.886, 0.886, 0.886, 0.1)),
+        )).add_child(text_entity).id();
+
+        app.update();
+
+        let state = app.world().resource::<RhythmState>();
+        assert_eq!(state.mode, RhythmMode::Constant); // Should not change
+
+        let background = app.world().get::<BackgroundColor>(button_entity).unwrap();
+        assert_eq!(background.0, Color::NONE);
+    }
+}