diff --git a/crates/bevy_input/src/input.rs b/crates/bevy_input/src/input.rs
index 72876dcd2da09..31e0b9980c4b0 100644
--- a/crates/bevy_input/src/input.rs
+++ b/crates/bevy_input/src/input.rs
@@ -71,3 +71,80 @@ where
         self.just_released.iter()
     }
 }
+
+#[cfg(test)]
+mod test {
+
+    #[test]
+    fn input_test() {
+        use crate::Input;
+
+        /// Used for testing `Input` functionality
+        #[derive(Copy, Clone, Eq, PartialEq, Hash)]
+        enum DummyInput {
+            Input1,
+            Input2,
+        }
+
+        let mut input = Input::default();
+
+        // Test pressing
+        input.press(DummyInput::Input1);
+        input.press(DummyInput::Input2);
+
+        // Check if they were "just pressed" (pressed on this update)
+        assert!(input.just_pressed(DummyInput::Input1));
+        assert!(input.just_pressed(DummyInput::Input2));
+
+        // Check if they are also marked as pressed
+        assert!(input.pressed(DummyInput::Input1));
+        assert!(input.pressed(DummyInput::Input2));
+
+        // Update the `Input` and check press state
+        input.update();
+
+        // Check if they're marked "just pressed"
+        assert!(!input.just_pressed(DummyInput::Input1));
+        assert!(!input.just_pressed(DummyInput::Input2));
+
+        // Check if they're marked as pressed
+        assert!(input.pressed(DummyInput::Input1));
+        assert!(input.pressed(DummyInput::Input2));
+
+        // Release the inputs and check state
+
+        input.release(DummyInput::Input1);
+        input.release(DummyInput::Input2);
+
+        // Check if they're marked as "just released" (released on this update)
+        assert!(input.just_released(DummyInput::Input1));
+        assert!(input.just_released(DummyInput::Input2));
+
+        // Check that they're not incorrectly marked as pressed
+        assert!(!input.pressed(DummyInput::Input1));
+        assert!(!input.pressed(DummyInput::Input2));
+
+        // Update the `Input` and check for removal from `just_released`
+
+        input.update();
+
+        // Check that they're not incorrectly marked as just released
+        assert!(!input.just_released(DummyInput::Input1));
+        assert!(!input.just_released(DummyInput::Input2));
+
+        // Set up an `Input` to test resetting.
+        let mut input = Input::default();
+
+        input.press(DummyInput::Input1);
+        input.release(DummyInput::Input2);
+
+        // Reset the `Input` and test it was reset correctly.
+        input.reset(DummyInput::Input1);
+        input.reset(DummyInput::Input2);
+
+        assert!(!input.just_pressed(DummyInput::Input1));
+        assert!(!input.pressed(DummyInput::Input1));
+
+        assert!(!input.just_released(DummyInput::Input2));
+    }
+}
diff --git a/crates/bevy_input/src/touch.rs b/crates/bevy_input/src/touch.rs
index 9e78f7d05bedf..1a23e240796fc 100644
--- a/crates/bevy_input/src/touch.rs
+++ b/crates/bevy_input/src/touch.rs
@@ -2,7 +2,6 @@ use bevy_app::{EventReader, Events};
 use bevy_ecs::{Local, Res, ResMut};
 use bevy_math::Vec2;
 use bevy_utils::HashMap;
-use core::ops::DerefMut;
 
 /// Represents a touch event
 ///
@@ -139,10 +138,8 @@ impl Touches {
         self.just_pressed.contains_key(&id)
     }
 
-    pub fn iter_just_pressed(&self) -> impl Iterator<Item = &Touch> + '_ {
-        self.just_pressed
-            .iter()
-            .map(move |(id, _)| self.pressed.get(id).unwrap())
+    pub fn iter_just_pressed(&self) -> impl Iterator<Item = &Touch> {
+        self.just_pressed.values()
     }
 
     pub fn get_released(&self, id: u64) -> Option<&Touch> {
@@ -153,54 +150,234 @@ impl Touches {
         self.just_released.contains_key(&id)
     }
 
-    pub fn iter_just_released(&self) -> impl Iterator<Item = &Touch> + '_ {
-        self.just_released
-            .iter()
-            .map(move |(id, _)| self.pressed.get(id).unwrap())
+    pub fn iter_just_released(&self) -> impl Iterator<Item = &Touch> {
+        self.just_released.values()
     }
 
     pub fn just_cancelled(&self, id: u64) -> bool {
         self.just_cancelled.contains_key(&id)
     }
 
-    pub fn iter_just_cancelled(&self) -> impl Iterator<Item = &Touch> + '_ {
-        self.just_cancelled
-            .iter()
-            .map(move |(id, _)| self.pressed.get(id).unwrap())
+    pub fn iter_just_cancelled(&self) -> impl Iterator<Item = &Touch> {
+        self.just_cancelled.values()
     }
-}
 
-/// Updates the Touches resource with the latest TouchInput events
-pub fn touch_screen_input_system(
-    mut state: Local<TouchSystemState>,
-    mut touch_state: ResMut<Touches>,
-    touch_input_events: Res<Events<TouchInput>>,
-) {
-    let touch_state = touch_state.deref_mut();
-    touch_state.just_pressed.clear();
-    touch_state.just_released.clear();
-    for event in state.touch_event_reader.iter(&touch_input_events) {
+    fn process_touch_event(&mut self, event: &TouchInput) {
         match event.phase {
             TouchPhase::Started => {
-                touch_state.pressed.insert(event.id, event.into());
-                touch_state.just_pressed.insert(event.id, event.into());
+                self.pressed.insert(event.id, event.into());
+                self.just_pressed.insert(event.id, event.into());
             }
             TouchPhase::Moved => {
-                let mut new_touch = touch_state.pressed.get(&event.id).cloned().unwrap();
+                let mut new_touch = self.pressed.get(&event.id).cloned().unwrap();
                 new_touch.previous_position = new_touch.position;
                 new_touch.previous_force = new_touch.force;
                 new_touch.position = event.position;
                 new_touch.force = event.force;
-                touch_state.pressed.insert(event.id, new_touch);
+                self.pressed.insert(event.id, new_touch);
             }
             TouchPhase::Ended => {
-                touch_state.just_released.insert(event.id, event.into());
-                touch_state.pressed.remove_entry(&event.id);
+                self.just_released.insert(event.id, event.into());
+                self.pressed.remove_entry(&event.id);
             }
             TouchPhase::Cancelled => {
-                touch_state.just_cancelled.insert(event.id, event.into());
-                touch_state.pressed.remove_entry(&event.id);
+                self.just_cancelled.insert(event.id, event.into());
+                self.pressed.remove_entry(&event.id);
             }
         };
     }
+
+    fn update(&mut self) {
+        self.just_pressed.clear();
+        self.just_released.clear();
+        self.just_cancelled.clear();
+    }
+}
+
+/// Updates the Touches resource with the latest TouchInput events
+pub fn touch_screen_input_system(
+    mut state: Local<TouchSystemState>,
+    mut touch_state: ResMut<Touches>,
+    touch_input_events: Res<Events<TouchInput>>,
+) {
+    touch_state.update();
+
+    for event in state.touch_event_reader.iter(&touch_input_events) {
+        touch_state.process_touch_event(event);
+    }
+}
+
+#[cfg(test)]
+mod test {
+
+    #[test]
+    fn touch_update() {
+        use crate::{touch::Touch, Touches};
+        use bevy_math::Vec2;
+
+        let mut touches = Touches::default();
+
+        let touch_event = Touch {
+            id: 4,
+            start_position: Vec2::new(0.0, 0.0),
+            start_force: None,
+            previous_position: Vec2::new(0.0, 0.0),
+            previous_force: None,
+            position: Vec2::new(0.0, 0.0),
+            force: None,
+        };
+
+        // Add a touch to `just_pressed`, 'just_released', and 'just cancelled'
+
+        touches.just_pressed.insert(4, touch_event);
+        touches.just_released.insert(4, touch_event);
+        touches.just_cancelled.insert(4, touch_event);
+
+        touches.update();
+
+        // Verify that all the `just_x` maps are cleared
+        assert!(touches.just_pressed.is_empty());
+        assert!(touches.just_released.is_empty());
+        assert!(touches.just_cancelled.is_empty());
+    }
+
+    #[test]
+    fn touch_process() {
+        use crate::{touch::TouchPhase, TouchInput, Touches};
+        use bevy_math::Vec2;
+
+        let mut touches = Touches::default();
+
+        // Test adding a `TouchPhase::Started`
+
+        let touch_event = TouchInput {
+            phase: TouchPhase::Started,
+            position: Vec2::new(4.0, 4.0),
+            force: None,
+            id: 4,
+        };
+
+        touches.update();
+        touches.process_touch_event(&touch_event);
+
+        assert!(touches.pressed.get(&touch_event.id).is_some());
+        assert!(touches.just_pressed.get(&touch_event.id).is_some());
+
+        // Test adding a `TouchPhase::Moved`
+
+        let moved_touch_event = TouchInput {
+            phase: TouchPhase::Moved,
+            position: Vec2::new(5.0, 5.0),
+            force: None,
+            id: touch_event.id,
+        };
+
+        touches.update();
+        touches.process_touch_event(&moved_touch_event);
+
+        assert_eq!(
+            touches
+                .pressed
+                .get(&moved_touch_event.id)
+                .expect("Missing from pressed after move.")
+                .previous_position,
+            touch_event.position
+        );
+
+        // Test cancelling an event
+
+        let cancel_touch_event = TouchInput {
+            phase: TouchPhase::Cancelled,
+            position: Vec2::new(1.0, 1.0),
+            force: None,
+            id: touch_event.id,
+        };
+
+        touches.update();
+        touches.process_touch_event(&cancel_touch_event);
+
+        assert!(touches.just_cancelled.get(&cancel_touch_event.id).is_some());
+        assert!(touches.pressed.get(&cancel_touch_event.id).is_none());
+
+        // Test ending an event
+
+        let end_touch_event = TouchInput {
+            phase: TouchPhase::Ended,
+            position: Vec2::new(4.0, 4.0),
+            force: None,
+            id: 4,
+        };
+
+        touches.update();
+        touches.process_touch_event(&touch_event);
+        touches.process_touch_event(&end_touch_event);
+
+        assert!(touches.just_released.get(&touch_event.id).is_some());
+        assert!(touches.pressed.get(&touch_event.id).is_none());
+    }
+
+    #[test]
+    fn touch_pressed() {
+        use crate::{touch::TouchPhase, TouchInput, Touches};
+        use bevy_math::Vec2;
+
+        let mut touches = Touches::default();
+
+        let touch_event = TouchInput {
+            phase: TouchPhase::Started,
+            position: Vec2::new(4.0, 4.0),
+            force: None,
+            id: 4,
+        };
+
+        // Register the touch and test that it was registered correctly
+        touches.process_touch_event(&touch_event);
+
+        assert!(touches.get_pressed(touch_event.id).is_some());
+        assert!(touches.just_pressed(touch_event.id));
+        assert_eq!(touches.iter().count(), 1);
+    }
+
+    #[test]
+    fn touch_released() {
+        use crate::{touch::TouchPhase, TouchInput, Touches};
+        use bevy_math::Vec2;
+
+        let mut touches = Touches::default();
+
+        let touch_event = TouchInput {
+            phase: TouchPhase::Ended,
+            position: Vec2::new(4.0, 4.0),
+            force: None,
+            id: 4,
+        };
+
+        // Register the touch and test that it was registered correctly
+        touches.process_touch_event(&touch_event);
+
+        assert!(touches.get_released(touch_event.id).is_some());
+        assert!(touches.just_released(touch_event.id));
+        assert_eq!(touches.iter_just_released().count(), 1);
+    }
+
+    #[test]
+    fn touch_cancelled() {
+        use crate::{touch::TouchPhase, TouchInput, Touches};
+        use bevy_math::Vec2;
+
+        let mut touches = Touches::default();
+
+        let touch_event = TouchInput {
+            phase: TouchPhase::Cancelled,
+            position: Vec2::new(4.0, 4.0),
+            force: None,
+            id: 4,
+        };
+
+        // Register the touch and test that it was registered correctly
+        touches.process_touch_event(&touch_event);
+
+        assert!(touches.just_cancelled(touch_event.id));
+        assert_eq!(touches.iter_just_cancelled().count(), 1);
+    }
 }
diff --git a/crates/bevy_math/src/face_toward.rs b/crates/bevy_math/src/face_toward.rs
index d090989fd4ccd..f873964b18afc 100644
--- a/crates/bevy_math/src/face_toward.rs
+++ b/crates/bevy_math/src/face_toward.rs
@@ -19,3 +19,23 @@ impl FaceToward for Mat4 {
         )
     }
 }
+
+#[cfg(test)]
+mod test {
+    #[test]
+    fn face_toward_mat4() {
+        use crate::{FaceToward, Mat4, Vec3, Vec4};
+
+        // Completely arbitrary arguments
+        let matrix = Mat4::face_toward(
+            Vec3::new(50.0, 60.0, 0.0),
+            Vec3::new(0.0, 0.0, 0.0),
+            Vec3::new(0.0, 1.0, 0.0),
+        );
+
+        assert_eq!(matrix.x_axis, Vec4::new(0.0, 0.0, -1.0, -0.0));
+        assert_eq!(matrix.y_axis, Vec4::new(-0.7682213, 0.6401844, 0.0, 0.0));
+        assert_eq!(matrix.z_axis, Vec4::new(0.6401844, 0.7682213, 0.0, 0.0));
+        assert_eq!(matrix.w_axis, Vec4::new(50.0, 60.0, 0.0, 1.0));
+    }
+}