tst_QQuickTextInput: Stabilize clipboard related functions on XCB

Even if compiled with QT_CONFIG(clipboard), a functional clipboard
might not be available on XCB (e.g. due to restrictions on CI VMs).

This patch adds an explicit test for XCB to platformquirks_p.h.
It skips the test functions canPaste() and canPasteEmpty().
As a drive-by it constifies local variables in canPaste() and
middleClickPaste() and unifies the skip message.

It also removes the BLACKLIST entries for clipboard-related tests on
opensuse.

Fixes: QTBUG-95940
Pick-to: 6.5
Change-Id: If6da9b589e98c1f63435f3d444567ce310ddee8a
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/quicktestutils/qml/platformquirks_p.h

@@ -36,7 +36,19 @@ struct PlatformQuirks
             CFRelease(pasteboard);
         return status == noErr;
 #else
-        return true;
+        if (QGuiApplication::platformName() != QLatin1StringView("xcb"))
+            return true;
+
+        // On XCB a clipboard may be dysfunctional due to platform restrictions
+        QClipboard *clipBoard = QGuiApplication::clipboard();
+        if (!clipBoard)
+            return false;
+        const QString &oldText = clipBoard->text();
+        QScopeGuard guard([&](){ clipBoard->setText(oldText); });
+        const QLatin1StringView prefix("Something to prefix ");
+        const QString newText = prefix + oldText;
+        clipBoard->setText(newText);
+        return QTest::qWaitFor([&](){ return clipBoard->text() == newText; });
 #endif
     }
 };

tests/auto/quick/qquicktextinput/BLACKLIST

@@ -2,14 +2,6 @@
 [mouseSelectionMode]
 opensuse-leap
 
-# QTBUG-99150
-[copyAndPaste]
-opensuse-leap
-
-# QTBUG-99150
-[canPaste]
-opensuse-leap
-
 # QTBUG-82058
 [setInputMask]
 macos ci
@@ -18,22 +10,6 @@ macos ci
 [passwordCharacter]
 ci b2qt 32bit
 
-# QTBUG-95940
-[canPaste]
-opensuse-leap
-
-# QTBUG-95940
-[canPasteEmpty]
-opensuse-leap
-
-# QTBUG-95940
-[copyAndPaste]
-opensuse-leap
-
-# QTBUG-95940
-[copyAndPasteKeySequence]
-opensuse-leap
-
 # QTBUG-103256
 [copyAndPasteKeySequence]
 android

tests/auto/quick/qquicktextinput/tst_qquicktextinput.cpp

@@ -2757,15 +2757,18 @@ void tst_qquicktextinput::copyAndPasteKeySequence()
 #if QT_CONFIG(clipboard) && QT_CONFIG(shortcut)
 void tst_qquicktextinput::canPasteEmpty()
 {
+    if (!PlatformQuirks::isClipboardAvailable())
+        QSKIP("This machine has no clipboard support.");
+
     QGuiApplication::clipboard()->clear();
 
-    QString componentStr = "import QtQuick 2.0\nTextInput { text: \"Hello world!\" }";
+    const QString componentStr = "import QtQuick 2.0\nTextInput { text: \"Hello world!\" }";
     QQmlComponent textInputComponent(&engine);
     textInputComponent.setData(componentStr.toLatin1(), QUrl());
     QQuickTextInput *textInput = qobject_cast<QQuickTextInput*>(textInputComponent.create());
     QVERIFY(textInput != nullptr);
 
-    bool cp = !textInput->isReadOnly() && QGuiApplication::clipboard()->text().size() != 0;
+    const bool cp = !textInput->isReadOnly() && QGuiApplication::clipboard()->text().size() != 0;
     QCOMPARE(textInput->canPaste(), cp);
 }
 #endif
@@ -2773,15 +2776,18 @@ void tst_qquicktextinput::canPasteEmpty()
 #if QT_CONFIG(clipboard) && QT_CONFIG(shortcut)
 void tst_qquicktextinput::canPaste()
 {
+    if (!PlatformQuirks::isClipboardAvailable())
+        QSKIP("This machine has no clipboard support.");
+
     QGuiApplication::clipboard()->setText("Some text");
 
-    QString componentStr = "import QtQuick 2.0\nTextInput { text: \"Hello world!\" }";
+    const QString componentStr = "import QtQuick 2.0\nTextInput { text: \"Hello world!\" }";
     QQmlComponent textInputComponent(&engine);
     textInputComponent.setData(componentStr.toLatin1(), QUrl());
     QQuickTextInput *textInput = qobject_cast<QQuickTextInput*>(textInputComponent.create());
     QVERIFY(textInput != nullptr);
 
-    bool cp = !textInput->isReadOnly() && QGuiApplication::clipboard()->text().size() != 0;
+    const bool cp = !textInput->isReadOnly() && QGuiApplication::clipboard()->text().size() != 0;
     QCOMPARE(textInput->canPaste(), cp);
 }
 #endif
@@ -2790,7 +2796,7 @@ void tst_qquicktextinput::canPaste()
 void tst_qquicktextinput::middleClickPaste()
 {
     if (!PlatformQuirks::isClipboardAvailable())
-        QSKIP("This machine doesn't support the clipboard");
+        QSKIP("This machine has no clipboard support.");
 
     QQuickView window(testFileUrl("mouseselectionmode_default.qml"));
 
@@ -2805,8 +2811,8 @@ void tst_qquicktextinput::middleClickPaste()
 
     textInputObject->setFocus(true);
 
-    QString originalText = textInputObject->text();
-    QString selectedText = "234567";
+    const QString originalText = textInputObject->text();
+    const QString selectedText = "234567";
 
     // press-and-drag-and-release from x1 to x2
     const QPoint p1 = textInputObject->positionToRectangle(2).center().toPoint();