Kittest utility toolbelt (#11435)

### Related

* Part of #8948 

### What

- Allows interacting with app state from an integration test using a
test hook function
- Adds a bunch of Rerun-specific utility functions to Kittest
- Replaces a context menu test from the release checklist as a proof of
concept

Author: aedm

Cargo.lock

@@ -8896,7 +8896,9 @@ dependencies = [
  "re_sdk",
  "re_server",
  "re_uri",
+ "re_view_text_document",
  "re_viewer",
+ "re_viewport_blueprint",
  "tempfile",
  "tokio",
 ]

crates/viewer/re_viewer/src/app_state.rs

@@ -32,6 +32,9 @@ use crate::{
 
 const WATERMARK: bool = false; // Nice for recording media material
 
+#[cfg(feature = "testing")]
+pub type TestHookFn = Box<dyn FnOnce(&ViewerContext<'_>)>;
+
 #[derive(serde::Deserialize, serde::Serialize)]
 #[serde(default)]
 pub struct AppState {
@@ -66,6 +69,12 @@ pub struct AppState {
     #[serde(skip)]
     pub(crate) share_modal: crate::ui::ShareModal,
 
+    /// Test-only: single-shot callback to run at the end of the frame. Used in integration tests
+    /// to interact with the `ViewerContext`.
+    #[cfg(feature = "testing")]
+    #[serde(skip)]
+    pub(crate) test_hook: Option<TestHookFn>,
+
     /// A stack of display modes that represents tab-like navigation of the user.
     #[serde(skip)]
     pub(crate) navigation: Navigation,
@@ -115,6 +124,9 @@ impl Default for AppState {
             view_states: Default::default(),
             selection_state: Default::default(),
             focused_item: Default::default(),
+
+            #[cfg(feature = "testing")]
+            test_hook: None,
         }
     }
 }
@@ -658,6 +670,12 @@ impl AppState {
                 self.open_url_modal.ui(ui);
                 self.share_modal
                     .ui(&ctx, ui, startup_options.web_viewer_base_url().as_ref());
+
+                // Only in integration tests: call the test hook if any.
+                #[cfg(feature = "testing")]
+                if let Some(test_hook) = self.test_hook.take() {
+                    test_hook(&ctx);
+                }
             }
         }
 

crates/viewer/re_viewer/src/viewer_test_utils/app_testing_ext.rs

@@ -0,0 +1,21 @@
+#![cfg(feature = "testing")]
+use re_viewer_context::StoreHub;
+
+use crate::App;
+
+pub trait AppTestingExt {
+    fn testonly_get_store_hub(&mut self) -> &mut StoreHub;
+    fn testonly_set_test_hook(&mut self, func: crate::app_state::TestHookFn);
+}
+
+impl AppTestingExt for App {
+    fn testonly_get_store_hub(&mut self) -> &mut StoreHub {
+        self.store_hub
+            .as_mut()
+            .expect("store_hub should be initialized")
+    }
+
+    fn testonly_set_test_hook(&mut self, func: crate::app_state::TestHookFn) {
+        self.state.test_hook = Some(func);
+    }
+}

crates/viewer/re_viewer/src/viewer_test_utils/mod.rs

@@ -1,3 +1,7 @@
+mod app_testing_ext;
+
+#[cfg(feature = "testing")]
+pub use app_testing_ext::AppTestingExt;
 use egui_kittest::Harness;
 use re_build_info::build_info;
 
@@ -6,11 +10,17 @@ use crate::{
     customize_eframe_and_setup_renderer,
 };
 
+#[derive(Default)]
+pub struct HarnessOptions {
+    pub window_size: Option<egui::Vec2>,
+}
+
 /// Convenience function for creating a kittest harness of the viewer App.
-pub fn viewer_harness() -> Harness<'static, App> {
+pub fn viewer_harness(options: &HarnessOptions) -> Harness<'static, App> {
+    let window_size = options.window_size.unwrap_or(egui::vec2(1024., 768.));
     Harness::builder()
         .wgpu()
-        .with_size(egui::vec2(1500., 1000.))
+        .with_size(window_size)
         .build_eframe(|cc| {
             cc.egui_ctx.set_os(egui::os::OperatingSystem::Nix);
             customize_eframe_and_setup_renderer(cc).expect("Failed to customize eframe");

crates/viewer/re_viewer/tests/app_kittest.rs

@@ -7,7 +7,7 @@ use egui_kittest::{SnapshotOptions, kittest::Queryable as _};
 
 use re_test_context::TestContext;
 use re_types::components::Colormap;
-use re_viewer::viewer_test_utils;
+use re_viewer::viewer_test_utils::{self, HarnessOptions};
 use re_viewer_context::{MaybeMutRef, ViewerContext};
 
 /// Navigates from welcome to settings screen and snapshots it.
@@ -20,7 +20,7 @@ async fn settings_screen() {
         std::env::set_var("TZ", "Europe/Stockholm");
     }
 
-    let mut harness = viewer_test_utils::viewer_harness();
+    let mut harness = viewer_test_utils::viewer_harness(&HarnessOptions::default());
     harness.get_by_label("Menu").click();
     harness.run_ok();
     harness.get_by_label_contains("Settings…").click();
@@ -45,7 +45,7 @@ async fn settings_screen() {
 /// Tests that certain recording-related entries are disabled (e.g. save or close recording).
 #[tokio::test]
 async fn menu_without_recording() {
-    let mut harness = viewer_test_utils::viewer_harness();
+    let mut harness = viewer_test_utils::viewer_harness(&HarnessOptions::default());
     harness.get_by_label("Menu").click();
     harness.run_ok();
     // Mask the shortcut for quitting, it's platform-dependent.

crates/viewer/re_viewer/tests/snapshots/menu_without_recording.png

@@ -11,18 +11,20 @@ version.workspace = true
 publish = false
 
 [dependencies]
+egui_kittest.workspace = true
+egui.workspace = true
 re_redap_client.workspace = true
 re_protos.workspace = true
 re_sdk.workspace = true
 re_server.workspace = true
 re_uri.workspace = true
+re_viewer = { workspace = true, features = ["testing"] }
+re_viewport_blueprint.workspace = true
 tempfile.workspace = true
 tokio = { workspace = true, features = ["rt-multi-thread", "macros"] }
 
 [dev-dependencies]
-re_viewer = { workspace = true, features = ["testing"] }
-egui_kittest.workspace = true
-egui.workspace = true
+re_view_text_document.workspace = true
 
 [lints]
 workspace = true