Harness: Add remove_cursor, event and event_modifiers (#7607)

* Closes #7591

Author: lucasmerlin

crates/egui_kittest/src/lib.rs

@@ -460,11 +460,15 @@ impl<'a, State> Harness<'a, State> {
         &mut self.state
     }
 
-    fn event(&self, event: egui::Event) {
+    /// Queue an event to be processed in the next frame.
+    pub fn event(&self, event: egui::Event) {
         self.queued_events.lock().push(EventType::Event(event));
     }
 
-    fn event_modifiers(&self, event: egui::Event, modifiers: Modifiers) {
+    /// Queue an event with modifiers.
+    ///
+    /// Queues the modifiers to be pressed, then the event, then the modifiers to be released.
+    pub fn event_modifiers(&self, event: egui::Event, modifiers: Modifiers) {
         let mut queue = self.queued_events.lock();
         queue.push(EventType::Modifiers(modifiers));
         queue.push(EventType::Event(event));
@@ -584,6 +588,16 @@ impl<'a, State> Harness<'a, State> {
         self.key_combination_modifiers(modifiers, &[key]);
     }
 
+    /// Remove the cursor from the screen.
+    ///
+    /// Will fire a [`egui::Event::PointerGone`] event.
+    ///
+    /// If you click a button and then take a snapshot, the button will be shown as hovered.
+    /// If you don't want that, you can call this method after clicking.
+    pub fn remove_cursor(&self) {
+        self.event(egui::Event::PointerGone);
+    }
+
     /// Mask something. Useful for snapshot tests.
     ///
     /// Call this _after_ [`Self::run`] and before [`Self::snapshot`].

crates/egui_kittest/tests/tests.rs

@@ -181,3 +181,36 @@ fn test_masking() {
 
     harness.snapshot("test_masking");
 }
+
+#[test]
+fn test_remove_cursor() {
+    let hovered = false;
+    let mut harness = Harness::new_ui_state(
+        |ui, state| {
+            let response = ui.button("Click me");
+            *state = response.hovered();
+        },
+        hovered,
+    );
+
+    harness.fit_contents();
+
+    harness.get_by_label("Click me").click();
+    harness.run();
+
+    assert!(harness.state(), "The button should be hovered");
+    let hovered_button_snapshot = harness.render().expect("Failed to render");
+
+    harness.remove_cursor();
+    harness.run();
+    assert!(
+        !harness.state(),
+        "The button should not be hovered after removing cursor"
+    );
+
+    let non_hovered_button_snapshot = harness.render().expect("Failed to render");
+    assert_ne!(
+        hovered_button_snapshot, non_hovered_button_snapshot,
+        "The button appearance should change"
+    );
+}