Android: enable tst_QScreen::grabWindow

Two things are done here:
- use showNormal() instead of show() to get an expected widget size.
- skip the test if HighDPI scaling is enabled with non-integer scaling
  factor, because there can be rounding errors.

Also had to backport the unconditional delay after showing the window
(introduced in 6.3), because the emulator was not fast enough to
actually render the window.

Fixes: QTBUG-87390
Change-Id: I653a17bac2142838b03a328e1629582384b6c7b3
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
(cherry picked from commit aa451b13b0914e3c33a4e05e792aa8c5effa7a3a)

2 files changed, 14 insertions, 7 deletions

diff --git a/tests/auto/gui/kernel/qscreen/BLACKLIST b/tests/auto/gui/kernel/qscreen/BLACKLIST
index 51fd672239..ca3136fdb2 100644
--- a/tests/auto/gui/kernel/qscreen/BLACKLIST
+++ b/tests/auto/gui/kernel/qscreen/BLACKLIST
@@ -1,5 +1,3 @@
-# QTBUG-87390
 [grabWindow]
-android
 # QTBUG-100412
 windows
diff --git a/tests/auto/gui/kernel/qscreen/tst_qscreen.cpp b/tests/auto/gui/kernel/qscreen/tst_qscreen.cpp
index 789069381b..5ae5028797 100644
--- a/tests/auto/gui/kernel/qscreen/tst_qscreen.cpp
+++ b/tests/auto/gui/kernel/qscreen/tst_qscreen.cpp
@@ -30,6 +30,7 @@
 #include <qrasterwindow.h>
 #include <qscreen.h>
 #include <qpa/qwindowsysteminterface.h>
+#include <private/qhighdpiscaling_p.h>
 
 #include <QTest>
 #include <QSignalSpy>
@@ -279,18 +280,26 @@ void tst_QScreen::grabWindow()
     QCOMPARE(screen->name().toUtf8(), screenName);
     const double screenDpr = screen->devicePixelRatio();
 
+    if (QHighDpiScaling::isActive()) {
+        const float rawFactor = QHighDpiScaling::factor(screen);
+        const float roundedFactor = qRound(rawFactor);
+        if (!qFuzzyCompare(roundedFactor, rawFactor))
+            QSKIP("HighDPI enabled with non-integer factor. Skip due to possible rounding errors.");
+    }
+
     Window window(screen);
     window.setGeometry(windowRect);
+#ifndef Q_OS_ANDROID
     window.show();
+#else
+    window.showNormal();
+#endif
 
     if (!QTest::qWaitForWindowExposed(&window))
         QSKIP("Failed to expose window - aborting");
 
-    if (QGuiApplication::platformName().startsWith(QLatin1String("xcb"), Qt::CaseInsensitive))
-        QTest::qWait(1500); // this is ridiculously necessary because of effects combined with slowness of VMs
-#ifdef Q_OS_MACOS // wait for desktop on screen to scroll into place
-    QTest::qWait(1000);
-#endif
+    // this is necessary because of scrolling effects combined with potential slowness of VMs
+    QTest::qWait(1500);
 
     QSize expectedGrabSize = grabRect.isValid() ? grabRect.size() : (grabWindow ?  windowRect.size() : screen->size());
     // we ask for pixel coordinates, but will get a pixmap with device-specific DPR