diff --git a/apps/effectcraft-cli/tests/cli.rs b/apps/effectcraft-cli/tests/cli.rs
index 723016a8..dd867790 100644
--- a/apps/effectcraft-cli/tests/cli.rs
+++ b/apps/effectcraft-cli/tests/cli.rs
@@ -373,7 +373,9 @@ fn mcp_autosave_survives_kill_and_restart_without_touching_desktop_settings() {
     assert_eq!(manifest["ended"], false);
     let mut restarted = McpChild::start(&config, true);
     let init = restarted.rpc("initialize", json!({}));
-    assert!(init["instructions"].as_str().unwrap().contains(path));
+    // The instructions carry the auto-save state as JSON, where a Windows path's backslashes
+    // are escaped.
+    assert!(init["instructions"].as_str().unwrap().contains(&Value::from(path).to_string()));
     assert_eq!(init["_meta"]["effectcraftAutoSave"]["previousSessions"][0]["autosave"], path);
     restarted.tool("open_project", json!({"path":path}));
     let comp = restarted.tool("get_comp", json!({"comp":"Survives restart"}));
diff --git a/crates/automation/src/tests.rs b/crates/automation/src/tests.rs
index 44a61cc1..e4b4f19e 100644
--- a/crates/automation/src/tests.rs
+++ b/crates/automation/src/tests.rs
@@ -269,7 +269,9 @@ fn autosave_is_durable_before_reply_and_queries_do_not_rotate() {
     drop(s); // Abrupt process loss has no EOF cleanup; the checkpoint already exists.
     let mut restarted = server().with_autosave(&dir).unwrap();
     let init = rpc(&mut restarted, 1, "initialize", json!({}));
-    assert!(init["instructions"].as_str().unwrap().contains(path));
+    // The instructions carry the auto-save state as JSON, where a Windows path's backslashes
+    // are escaped.
+    assert!(init["instructions"].as_str().unwrap().contains(&Value::from(path).to_string()));
     assert_eq!(init["_meta"]["effectcraftAutoSave"]["previousSessions"][0]["autosave"], path);
     call_json(&mut restarted, "open_project", json!({"path": path}));
     assert_eq!(call_json(&mut restarted, "get_project", json!({}))["items"][0]["name"], "Durable");
diff --git a/crates/ui-egui/tests/ui_audio_scrub.rs b/crates/ui-egui/tests/ui_audio_scrub.rs
index 01843de7..02fefb14 100644
--- a/crates/ui-egui/tests/ui_audio_scrub.rs
+++ b/crates/ui-egui/tests/ui_audio_scrub.rs
@@ -119,7 +119,13 @@ fn cmd_dragging_the_current_time_scrubs_and_an_idle_scrub_closes() {
 #[test]
 fn preview_with_audio_shows_every_frame_and_sounds_once_cached() {
     let fake = Fake::default();
-    let (app, cid) = setup(true, &fake);
+    let (mut app, cid) = setup(true, &fake);
+    // Playback requests at most twice as many frames ahead per step as there are render threads.
+    // Four times that many frames take at least four steps to cache, so frames are shown silently
+    // first however fast the renderer is (with a fixed 2 s comp, a machine with many cores cached
+    // all of it before the first step and the sound started at once).
+    let ahead = (app.frames.parallelism() * 2).max(4);
+    app.session.execute("comp.settings", json!({"comp": cid.0, "duration": (4 * ahead) as f64 / 30.0})).unwrap();
     // A little under one frame of input time per step.
     let mut h = Harness::builder().with_size(egui::vec2(1400.0, 900.0)).with_step_dt(1.0 / 31.0).build_eframe(|_| app);
     h.run_steps(2);
diff --git a/crates/ui-egui/tests/ui_gpu.rs b/crates/ui-egui/tests/ui_gpu.rs
index 4aca21a5..92d18a44 100644
--- a/crates/ui-egui/tests/ui_gpu.rs
+++ b/crates/ui-egui/tests/ui_gpu.rs
@@ -19,20 +19,45 @@ fn settle(h: &mut Harness<'_, EffectcraftApp>) {
     }
 }
 
+/// egui_kittest's wgpu setup on the adapter the headless compositor picked (`name (Backend)`),
+/// like the desktop app's window. Left alone, egui_kittest prefers a CPU adapter, which on
+/// Windows is WARP on DirectX 12, where FXC fails to compile the compositor's kernels: the
+/// viewer would stay on the CPU and the comparison would never run.
+fn same_adapter(name: String) -> eframe::egui_wgpu::WgpuSetup {
+    let mut setup = egui_kittest::wgpu::default_wgpu_setup();
+    if let eframe::egui_wgpu::WgpuSetup::CreateNew(c) = &mut setup {
+        let fallback = c.native_adapter_selector.take();
+        c.native_adapter_selector = Some(std::sync::Arc::new(move |adapters, surface| {
+            let named = |a: &&eframe::wgpu::Adapter| format!("{} ({:?})", a.get_info().name, a.get_info().backend) == name;
+            match (adapters.iter().find(named), &fallback) {
+                (Some(a), _) => Ok(a.clone()),
+                (None, Some(f)) => f(adapters, surface),
+                (None, None) => adapters.first().cloned().ok_or_else(|| "No adapter found".to_owned()),
+            }
+        }));
+    }
+    setup
+}
+
 #[test]
 fn viewer_draws_gpu_frames_that_match_the_cpu() {
     let Some(probe) = effectcraft_gpu::Gpu::headless() else {
         eprintln!("no GPU adapter: skipping");
         return;
     };
-    eprintln!("headless compositor adapter: {}", effectcraft_engine::render::Accelerator::name(&probe));
+    let adapter = effectcraft_engine::render::Accelerator::name(&probe);
+    eprintln!("headless compositor adapter: {adapter}");
     // egui-wgpu creates its GL device with WebGL2's limits, which the compositor declines.
-    let gl = effectcraft_engine::render::Accelerator::name(&probe).ends_with("(Gl)");
+    let gl = adapter.ends_with("(Gl)");
     drop(probe);
     let mut s = Session::default();
     s.execute("file.openDemoProject", json!({})).unwrap();
     s.execute("time.set", json!({"time": 2.0})).unwrap();
-    let mut h = Harness::builder().with_size(egui::vec2(1400.0, 900.0)).with_pixels_per_point(1.0).wgpu().build_eframe(|_| EffectcraftApp::new(s));
+    let mut h = Harness::builder()
+        .with_size(egui::vec2(1400.0, 900.0))
+        .with_pixels_per_point(1.0)
+        .wgpu_setup(same_adapter(adapter))
+        .build_eframe(|_| EffectcraftApp::new(s));
     settle(&mut h);
     if gl && h.state().gpu_adapter().is_none() {
         eprintln!("egui-wgpu's GL device has WebGL2 limits: the viewer stays on the CPU, skipping");