14.20 round 1: the whole picture guarded, origins, streaks and the restarted wait tested

tests/NavigatorFailureTests.cpp

@@ -0,0 +1,55 @@
+#include "AddressSpaceLimit.h"
+#include "Document/EditorSession.h"
+#include "Rendering/RasterSnapshot.h"
+#include "UI/NavigatorMinimap.h"
+#include <QSettings>
+#include <QStandardPaths>
+#include <QtTest>
+#include <malloc.h>
+
+// The Navigator when a painted layer cannot flatten.
+class NavigatorFailureTests : public QObject {
+    Q_OBJECT
+private slots:
+    void aFlattenThatFindsNoMemoryDrawsNoPicture();
+};
+
+void NavigatorFailureTests::aFlattenThatFindsNoMemoryDrawsNoPicture()
+{
+    QStandardPaths::setTestModeEnabled(true);
+    NavigatorMinimap::setVisibleSetting(true);
+    // 4000 by 3000 painted from two pixels: 48 MB flat.
+    QImage base(2, 2, QImage::Format_RGBA8888_Premultiplied);
+    base.fill(Qt::red);
+    EditorSession session;
+    session.createDocument(4000, 3000);
+    session.insert(ImportedImage(std::make_shared<const RasterSnapshot>(4000, 3000, base, QRectF(0, 0, 2, 2), std::vector<BrushPatch>{}), QImage(),
+                                 QStringLiteral("Painted")));
+    session.viewport.resize(QSizeF(800, 600), 1, QSizeF(4000, 3000));
+    std::optional<QImage> starved;
+    {
+        const AddressSpaceLimit limit(8ll << 20);
+        QTest::ignoreMessage(QtWarningMsg, QRegularExpression("the navigator's picture could not be made"));
+        starved = session.navigatorImage(300);
+        // The minimap shows without a picture, never throwing.
+        NavigatorMinimap minimap(session);
+        session.zoom(4, session.viewport.center());
+        QVERIFY(!minimap.isHidden() && minimap.picture().isNull());
+    }
+    QVERIFY(!starved);
+    // With room again it draws: the base's corner, then clear.
+    const QImage drawn = session.navigatorImage(300).value();
+    QVERIFY(drawn.size() == QSize(300, 225) && drawn.pixelColor(150, 100).alpha() == 0);
+    QSettings().remove(QLatin1String(NavigatorMinimap::visibleKey));
+}
+
+int main(int argc, char **argv)
+{
+    // Large asks map memory the limit counts.
+    mallopt(M_MMAP_THRESHOLD, 64 * 1024);
+    QApplication app(argc, argv);
+    NavigatorFailureTests tests;
+    return QTest::qExec(&tests, argc, argv);
+}
+
+#include "NavigatorFailureTests.moc"