Run a frame per queued event in egui_kittest (emilk#5704)

This should fix the remaining problems with the modifiers
* [x] I have followed the instructions in the PR template

Author: lucasmerlin

crates/egui_kittest/src/event.rs

@@ -8,14 +8,12 @@ pub(crate) struct EventState {
 }
 
 impl EventState {
-    /// Map the kittest events to egui events, add them to the input and update the modifiers.
+    /// Map the kittest event to an egui event, add it to the input and update the modifiers.
     /// This function accesses `egui::RawInput::modifiers`. Make sure it is not reset after each
     /// frame (Since we use [`egui::RawInput::take`], this should be fine).
-    pub fn update(&mut self, events: Vec<kittest::Event>, input: &mut egui::RawInput) {
-        for event in events {
-            if let Some(event) = self.kittest_event_to_egui(&mut input.modifiers, event) {
-                input.events.push(event);
-            }
+    pub fn update(&mut self, event: kittest::Event, input: &mut egui::RawInput) {
+        if let Some(event) = self.kittest_event_to_egui(&mut input.modifiers, event) {
+            input.events.push(event);
         }
     }
 

crates/egui_kittest/src/lib.rs

@@ -219,17 +219,22 @@ impl<'a, State> Harness<'a, State> {
         self
     }
 
-    /// Run a frame.
-    /// This will call the app closure with the queued events and current context and
+    /// Run a frame for each queued event (or a single frame if there are no events).
+    /// This will call the app closure with each queued event and
     /// update the Harness.
     pub fn step(&mut self) {
-        self._step(false);
+        let events = self.kittest.take_events();
+        if events.is_empty() {
+            self._step(false);
+        }
+        for event in events {
+            self.event_state.update(event, &mut self.input);
+            self._step(false);
+        }
     }
 
+    /// Run a single step. This will not process any events.
     fn _step(&mut self, sizing_pass: bool) {
-        self.event_state
-            .update(self.kittest.take_events(), &mut self.input);
-
         self.input.predicted_dt = self.step_dt;
 
         let mut output = self.ctx.run(self.input.take(), |ctx| {

crates/egui_kittest/tests/tests.rs

@@ -22,6 +22,7 @@ fn test_modifiers() {
     struct State {
         cmd_clicked: bool,
         cmd_z_pressed: bool,
+        cmd_y_pressed: bool,
     }
     let mut harness = Harness::new_ui_state(
         |ui, state| {
@@ -31,6 +32,9 @@ fn test_modifiers() {
             if ui.input(|i| i.modifiers.command && i.key_pressed(egui::Key::Z)) {
                 state.cmd_z_pressed = true;
             }
+            if ui.input(|i| i.modifiers.command && i.key_pressed(egui::Key::Y)) {
+                state.cmd_y_pressed = true;
+            }
         },
         State::default(),
     );
@@ -39,18 +43,17 @@ fn test_modifiers() {
     // This run isn't necessary, but allows us to test whether modifiers are remembered between frames
     harness.run();
     harness.get_by_label("Click me").click();
-    // TODO(lucasmerlin): Right now the key_up needs to happen on a separate frame or it won't register.
-    // This should be more intuitive
-    harness.run();
     harness.get_by_label("Click me").key_up(Key::Command);
-
     harness.run();
 
     harness.press_key_modifiers(Modifiers::COMMAND, egui::Key::Z);
-    // TODO(lucasmerlin): This should also work (Same problem as above)
-    // harness.node().key_combination(&[Key::Command, Key::Z]);
+    harness.run();
+
+    harness.node().key_combination(&[Key::Command, Key::Y]);
+    harness.run();
 
     let state = harness.state();
     assert!(state.cmd_clicked, "The button wasn't command-clicked");
     assert!(state.cmd_z_pressed, "Cmd+Z wasn't pressed");
+    assert!(state.cmd_y_pressed, "Cmd+Y wasn't pressed");
 }