it: test dnd focus change on drop

src/it/tests/t0025_dnd_focus_change.rs

@@ -0,0 +1,51 @@
+use {
+    crate::{
+        ifs::wl_seat::BTN_LEFT,
+        it::{test_error::TestResult, test_utils::test_rect_ext::TestRectExt, testrun::TestRun},
+        tree::Node,
+    },
+    std::rc::Rc,
+};
+
+testcase!();
+
+async fn test(run: Rc<TestRun>) -> TestResult {
+    let ds = run.create_default_setup().await?;
+
+    let client = run.create_client().await?;
+
+    let win1 = client.create_window().await?;
+    win1.map2().await?;
+    let win2 = client.create_window().await?;
+    win2.map2().await?;
+
+    let seat = client.get_default_seat().await?;
+    let button = seat.pointer.button.expect()?;
+
+    let (x, y) = win1.tl.server.node_absolute_position().center();
+    ds.move_to(x, y);
+    let click = ds.mouse.click(BTN_LEFT);
+
+    client.sync().await;
+    let dev = client.data_device_manager.get_data_device(&seat.seat)?;
+    let src = client.data_device_manager.create_data_source()?;
+    src.set_actions(1)?;
+    dev.start_drag(&src, &win1.surface, None, button.next()?.serial)?;
+
+    client.sync().await;
+    let enter = seat.pointer.enter.expect()?;
+
+    let (x, y) = win2.tl.server.node_absolute_position().center();
+    ds.move_to(x, y);
+
+    client.sync().await;
+    tassert!(enter.next().is_err());
+
+    drop(click);
+
+    client.sync().await;
+    client.sync().await;
+    tassert_eq!(enter.next()?.surface, win2.surface.id);
+
+    Ok(())
+}