[autotests] Extend PlasmaSurface to verify position of OSD windows

This adds a new test case which maps an OSD window and verifies that it's
positioned correctly. Then an additional screen is added which should not
affect the position, but as the test case shows: it does affect the
position.

CCBUG: 366696

autotests/integration/plasma_surface_test.cpp

@@ -20,6 +20,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "kwin_wayland_test.h"
 #include "platform.h"
 #include "shell_client.h"
+#include "screens.h"
 #include "wayland_server.h"
 #include "workspace.h"
 #include <KWayland/Client/connection_thread.h>
@@ -50,6 +51,7 @@ private Q_SLOTS:
     void testAcceptsFocus();
 
     void testDesktopIsOpaque();
+    void testOSDPlacement();
 
 private:
     ConnectionThread *m_connection = nullptr;
@@ -199,5 +201,40 @@ void PlasmaSurfaceTest::testDesktopIsOpaque()
     QCOMPARE(c->depth(), 24);
 }
 
+void PlasmaSurfaceTest::testOSDPlacement()
+{
+    QScopedPointer<Surface> surface(Test::createSurface());
+    QVERIFY(!surface.isNull());
+    QScopedPointer<ShellSurface> shellSurface(Test::createShellSurface(surface.data()));
+    QVERIFY(!shellSurface.isNull());
+    QScopedPointer<PlasmaShellSurface> plasmaSurface(m_plasmaShell->createSurface(surface.data()));
+    QVERIFY(!plasmaSurface.isNull());
+    plasmaSurface->setRole(PlasmaShellSurface::Role::OnScreenDisplay);
+
+    // now render and map the window
+    auto c = Test::renderAndWaitForShown(surface.data(), QSize(100, 50), Qt::blue);
+
+    QVERIFY(c);
+    QCOMPARE(c->windowType(), NET::OnScreenDisplay);
+    QVERIFY(c->isOnScreenDisplay());
+    QCOMPARE(c->geometry(), QRect(590, 649, 100, 50));
+
+    // change the screen size
+    QSignalSpy screensChangedSpy(screens(), &Screens::changed);
+    QVERIFY(screensChangedSpy.isValid());
+    const QVector<QRect> geometries{QRect(0, 0, 1280, 1024), QRect(1280, 0, 1280, 1024)};
+    QMetaObject::invokeMethod(kwinApp()->platform(), "outputGeometriesChanged",
+                              Qt::DirectConnection,
+                              Q_ARG(QVector<QRect>, geometries));
+    QVERIFY(screensChangedSpy.wait());
+    QCOMPARE(screensChangedSpy.count(), 1);
+    QCOMPARE(screens()->count(), 2);
+    QCOMPARE(screens()->geometry(0), geometries.at(0));
+    QCOMPARE(screens()->geometry(1), geometries.at(1));
+
+    QEXPECT_FAIL("", "Geometry should not change due to a screen being added", Continue);
+    QCOMPARE(c->geometry(), QRect(590, 649, 100, 50));
+}
+
 WAYLANDTEST_MAIN(PlasmaSurfaceTest)
 #include "plasma_surface_test.moc"