tst_QPixmapCache: check insert() reports failure

None of the existing tests failed when I started to return a valid key
from a failed insert(QPixmap), so add a test that would fail.

Pick-to: 6.6 6.5 6.2 5.15
Change-Id: I74f23d2ec4c04151f8f1266c0c503713d4642f3a
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 28 insertions, 0 deletions

diff --git a/tests/auto/gui/image/qpixmapcache/tst_qpixmapcache.cpp b/tests/auto/gui/image/qpixmapcache/tst_qpixmapcache.cpp
index 407117c75b..84b4831768 100644
--- a/tests/auto/gui/image/qpixmapcache/tst_qpixmapcache.cpp
+++ b/tests/auto/gui/image/qpixmapcache/tst_qpixmapcache.cpp
@@ -31,6 +31,7 @@ private slots:
     void setCacheLimit();
     void find();
     void insert();
+    void failedInsertReturnsInvalidKey();
     void replace();
     void remove();
     void clear();
@@ -269,6 +270,7 @@ void tst_QPixmapCache::insert()
     for (int i = 0; i < numberOfKeys; ++i) {
         QPixmap p3(10,10);
         keys.append(QPixmapCache::insert(p3));
+        QVERIFY(keys.back().isValid());
     }
 
     num = 0;
@@ -282,6 +284,32 @@ void tst_QPixmapCache::insert()
     QVERIFY(num <= estimatedNum);
 }
 
+void tst_QPixmapCache::failedInsertReturnsInvalidKey()
+{
+    //
+    // GIVEN: a pixmap whose memory footprint exceeds the cache's limit:
+    //
+    QPixmapCache::setCacheLimit(20);
+
+    QPixmap pm(256, 256);
+    pm.fill(Qt::transparent);
+    QCOMPARE_GT(pm.width() * pm.height() * pm.depth() / 8,
+                QPixmapCache::cacheLimit() * 1024);
+
+    //
+    // WHEN: trying to add this pixmap to the cache
+    //
+    const auto success = QPixmapCache::insert(u"foo"_s, pm); // QString API
+    { QPixmap r; QVERIFY(!QPixmapCache::find(u"foo"_s, &r)); }
+    const auto key = QPixmapCache::insert(pm);               // "int" API
+
+    //
+    // THEN: failure is reported to the user
+    //
+    QVERIFY(!key.isValid()); // "int" API
+    QVERIFY(!success);       // QString API
+}
+
 void tst_QPixmapCache::replace()
 {
     //The int part of the API